- Created By: Sarang Holey
- Date: June-2020
- This Repo contain step by step Java Topics for training purposes.
- You can download the project and import as Maven Project in Eclipse or IntelliJ in order to execute the programs.
- Reach out for more details about this repo: [email protected] / [email protected]
Bringing the code in this File as well so as to have a consolidated view of all the Basic Java Programs.
Click here-Data Types in Java, String Concat
package _1_Session._1_DataTypesInJava;
/**
*
* @author Sarang
* Date - 01-10-2020
*
*/
/*
* Here in this class data types in java covered
* Data types -
* 1. Primitive Data types
* These Data Types stored in memory without any object creation
* and the size of storing them is already defined in java.
* Ex - byte, short, int, long, double, char, boolean
*
* 2. Non - Primitive Data types
* They are stored in the form of objects in memory.
* Ex - String, Array, List, Set
*/
public class _1_Different_Data_Types {
public static void main(String[] args) {
// Declaring a variable
int height;
// initialization of a variable
height = 10;
// Declaring & initialization a variable
int ageOfUser = 16; // with camel casing
int age_of_user = 20; // by using underscore symbol
// 1. Primitive Data types
// ***********************************************************
// ********************** Integer Family *********************
// ***********************************************************
// byte 1 byte | range -127 to 128 |
byte width = 10;
byte temperature = -12;
byte score = 00;
byte weekDayNumber = 1;
// short 2 byte | range -32768 to 32767 |
short s1 = 100;
short s2 = -5678;
short s3 = 00;
// int 4 bytes | range -1247483648 to 2147483647 |
int i1 = 10;
int i2 = 23;
int i3 = 0;
// long 8 byte | range very long no need to memorize |
long l1 = 10;
long l2 = -5645;
long l3 = 00;
// ***********************************************************
// ******* floating point numbers (Decimal Numbers) **********
// ***********************************************************
// float 4 byte | range very long no need to memorize |
float interestRate = 12.33f;
float f2 = (float)12.33;
float f3 = 75f;
float f4 = 56; // 56.00
float f5 = 0.00f;
// double 8 bytes | range very long no need to memorize |
double d1 = 12.33333333;
double d2 = 56;
double d3 = 89.00;
double d4 = 0;
// ***********************************************************
// ********************* boolean family **********************
// ***********************************************************
// boolean 1 bit [not perfectly defined in java docs] | range true / false |
boolean isIndianNationality = true; // 1
boolean e2 = false; // 0
// ***********************************************************
// ********************* character family ********************
// ***********************************************************
//char 2 byte | it will accept Single character |
char c1 = 'a';
char c2 = '8';
char c3 = '0';
char c4 = '$';
char c5 = '@';
char c6 = '|';
// 2. Non - Primitive Data types
// ***********************************************************
// ********************* String (it's a Class) ***************
// ***********************************************************
// String is a collection of characters (char) so size/range vary depending on usages.
String javaVersion = "Currently Running on Java 1.8";
String employeeId = "56451";
String password = "2@45#";
// ***********************************************************
// ******** Printing the Values of different data types ******
// ***********************************************************
System.out.println("Primitive Data Types");
System.out.println("Printing byte values ---->");
System.out.println(width);
System.out.println(temperature);
System.out.println(score);
System.out.println("--------------------------");
System.out.println("Printing short values --->");
System.out.println(s1);
System.out.println(s2);
System.out.println(s3);
System.out.println("--------------------------");
System.out.println("Printing integer values -->");
System.out.println(i1);
System.out.println(i2);
System.out.println(i3);
System.out.println("---------------------------");
System.out.println("Printing long values ----->");
System.out.println(l1);
System.out.println(l2);
System.out.println(l3);
System.out.println("---------------------------");
System.out.println("Printing float values ----->");
System.out.println(interestRate);
System.out.println(f2);
System.out.println(f3);
System.out.println(f4);
System.out.println(f5);
System.out.println("---------------------------");
System.out.println("Printing double values --->");
System.out.println(d1);
System.out.println(d2);
System.out.println(d3);
System.out.println(d4);
System.out.println("---------------------------");
System.out.println("Printing boolean values -->");
System.out.println(isIndianNationality);
System.out.println(e2);
System.out.println("---------------------------");
System.out.println("Printing char values ----->");
System.out.println(c1);
System.out.println(c2);
System.out.println(c3);
System.out.println(c4);
System.out.println(c5);
System.out.println("---------------------------");
System.out.println("Non - Primitive Data types ");
System.out.println("Printing String values --->");
System.out.println(javaVersion);
System.out.println(employeeId);
System.out.println(password);
System.out.println("---------------------------");
}
}
package _1_Session._2_StringAndCharacterConcatination;
/**
*
* @author Sarang
* Date - 01-10-2020
*
*/
/*
* Here in this class String concatenation in java covered
* concatenation - merging or adding the values
*/
public class _2_String_And_Character_Concatination {
public static void main(String[] args) {
// *************************************************
// 1. String Concatenation
// *************************************************
String x = "Test";
String y = "Seleium";
String c = "100";
String d = "200";
int a = 100;
int b = 200;
System.out.println("\n---------------------------------\n");
// 1.
System.out.println(a+b); // 300
// 2.
System.out.println(x+y); // TestSeleium
// 3.
System.out.println(a+b+x); // 300Test
// 4.
System.out.println(a+b+x+y); // 300TestSeleium
// 5.
System.out.println(x+y+a); // TestSeleium100
// 6.
System.out.println(x+y+a+b); // TestSeleium100 + 200 = TestSelenium100200
System.out.println(c+d); // 100200
// Use case
int bill = 520;
int tax = 30;
//int total = bill+tax;
//System.out.println("Food Bill is : " + total);
System.out.println("Food Bill is : " + (bill+tax));
// *************************************************
// 2. Character Concatenation
// *************************************************
char c1 = '5'; int z1 = 5;
char c2 = '4'; int z2 = 4;
char c3 = 'A'; String q1 = "A";
char c4 = 'B'; String q2 = "B";
System.out.println(c1+c2);
System.out.println(z1+z2);
System.out.println("-----------");
System.out.println(c3+c4);
System.out.println(q1+q2);
}
}
package _1_Session._3_IncrementAndDecrementOperator;
public class _3_Incremental_And_Decremental {
public static void main(String[] args) {
// ++ and --
// int a = 1;
// a = a+1;
// System.out.println(a);
System.out.println("*********** pre increment **********");
int i = 1;
int j = ++i; //pre increment
System.out.println(i); // 2
System.out.println(j); // 2
System.out.println("*********** post increment **********");
int p = 1;
int q = p++; //post increment
System.out.println(p); // 2
System.out.println(q); // 1
System.out.println("*********** pre decrement **********");
int m = 2;
int n = --m; //pre decrement
System.out.println(m); // 1
System.out.println(n); // 1
System.out.println("*********** post decrement **********");
int c = 0;
int d = c--;
System.out.println(c); // -1
System.out.println(d); // 0
int f = -1;
int g = --f;
System.out.println(f); // -2
System.out.println(g); // -2
}
}Click here-Conditional Operator-If Else, Switch Case
package _2_Session._1_Conditional_Operators;
public class _1_Conditional_Operators {
public static void main(String[] args) {
// Conditional operators are used to check & compare the
// condition between the variables & values
// Ex 1. == :- Comparison operator
// 2. > :- Greater than operator
// 3. < :- Less than operator
// 4. >= :- Greater than equal to operator
// 5. <= :- Less than equal to operator
// 6. != :- Not equal to operator
// 7. && :- AND / Short Circuit operator
// 8. || :- OR operator
int a = 10;
int b = 20;
// // Example - 1
// // Compare (Validate) which one is greater between two values
// if(b > a)
// {
// System.out.println("b is greater than a");
// }
// else // optional part not necessary to write every time
// {
// System.out.println("a is greater than b");
// }
//
// System.out.println("----------------------------------------");
// Example - 2
// Compare (Validate) which one is greater between two values
// Or are the two values are same
if(b == a)
{
System.out.println("both values are equal");
}
else if(b > a)
{
System.out.println("b is greater than a");
}
else // optional part not necessary to write everytime
{
System.out.println("a is greater than b");
}
System.out.println("----------------------------------------");
// Example - 3
// Compare (Validate) which one is greater between two values
// Or are the two values are same
if(b >= a)
{
System.out.println("b is greater than a or equal to a");
}
else
{
System.out.println("b is less than a or equal to a");
}
System.out.println("----------------------------------------");
// Example - 4
// Not equal to operator
int total = 100;
if(!(total == 0)) // total == 0 is false and !false equals to true
{
System.out.println("this is bill is eligible for 10% discount");
}
else {
System.out.println("this is bill is not eligible for discount");
}
// Example - 5
// Dead code - A part of code which will not executed any time
// even though its syntactically correct
// if statement needs always a true condition to execute the code
// try for not equal to operator
if(false)
{
System.out.println("Hello there, How are you");
}
else
{
System.out.println("Good bye");
}
System.out.println("----------------------------------------");
// Example - 6
// Nested if
int num = 15;
if(num > 10)
{
if(num == 15)
{
System.out.println("Number is equal to 15");
}
if(num == 17)
{
System.out.println("Number is equal to 17");
}
}
else {
System.out.println("number is less than or equal to 10");
}
System.out.println("----------------------------------------");
// Example - 7
// Nested if - else if
int number = 10; //10 40 50
if(number == 10)
{
System.out.println("The number is 10");
}
else if (number == 20)
{
System.out.println("The number is 20");
}
else if (number == 30)
{
System.out.println("The number is 30");
}
else {
System.out.println("number is not found...");
}
System.out.println("----------------------------------------");
// Example - 8
// && operator - true && true = true
// - false && true = false
// - true && false = false
// - false && false = false
// WAP to find highest number form 3 numbers
int x = 100;
int y = 200;
int z = 300;
if(x>y && x>z)
{
System.out.println("x is the higest number");
}
else if (y>z)
{
System.out.println("y is the higest number");
}
else
{
System.out.println("z is the higest number");
}
System.out.println("----------------------------------------");
// Example - 8
// || operator - true && true = true
// - false || true = true
// - true || false = true
// - false || false = false
String UserName = "Manish";
if (UserName == "Tom" || UserName == "Peter") {
System.out.println("Hi developer " + UserName);
System.out.println("How may I help you?");
}
else if (UserName == "Steve" || UserName == "Joe")
{
System.out.println("Hi tester " + UserName);
System.out.println("How may I help you?");
}
else {
System.out.println("Hi there " + UserName);
System.out.println("How may I help you?");
}
}
}package _2_Session._2_SwitchCase_Concept;
public class _1_SwitchCase_Statement {
public static void main(String[] args) {
// Switch Case is used to check multiple conditions
// In switch case String & integer are used to switch between
// different cases
// Performance wise switch case is good than if else
// Example - 1
int number = 2;
switch (number) {
case 0 :
System.out.println("Number is zero");
break;
case 1:
System.out.println("Number is one");
break;
case 2:
System.out.println("Number is two");
break;
case 3:
System.out.println("Number is three");
break;
case 4:
System.out.println("Number is four");
break;
case 5:
System.out.println("Number is five");
break;
case 6:
System.out.println("Number is six");
break;
case 7:
System.out.println("Number is seven");
break;
case 8:
System.out.println("Number is eight");
break;
case 9:
System.out.println("Number is nine");
break;
default:
System.out.println("Enter a number between Zero to Nine ");
break;
}
System.out.println("------------------------------------");
// Example - 2
// Switch case without break statement
int p = 2;
switch (p) {
case 1:
case 2:
System.out.println("Hello");
case 3:
case 4:
System.out.println("Hi");
break;
default:
break;
}
// use case - browser switching
// Example - 3
String browser = "chrome";
switch (browser) {
case "chrome":
System.out.println("Chrome browser invoked");
break;
case "firefox":
System.out.println("Firefox browser invoked");
break;
default:
System.out.println("safari browser is not implemented");
break;
}
}
}Click here-Looping
package _3_Session._1_While_Loop;
public class _1_While_loop {
public static void main(String[] args) {
// To iterate some value or execute some line of code
// in a loop with some condition
// To print 1 to 5 integer
// Worst way of of printing by coding
System.out.println(1);
System.out.println(2);
System.out.println(3);
System.out.println(4);
System.out.println(5);
System.out.println("-----------------------------");
// To print 1 to 10 integer
// While loop
int i = 1; // Start Point
while(i<=10) // condition
{
// Iteration
System.out.println(i); // 1 2 3 ..... 10
// Condition to increase the counter value
// otherwise the loop
i++; // (++i) or (i=i+1) also fine here
}
System.out.println("-----------------------------");
// Example - Print the statement when loop
// reaches to number 5
int j = 1;
while(j<=10) // condition
{
// Iteration
System.out.println(j); // 1 2 3 4
if(j == 5)
{
System.out.println("Hey this is Five here");
// if after number 5 if no need to print next numbers use break
//break;
}
// Condition to increase the counter value
j++; // (++j) or (j=j+1) also fine here
}
System.out.println("-----------------------------");
// Example - After received cash from customer on billing counter
// by using boolean condition in while loop
boolean isCashReceived = true;
int amount = 250;
while(isCashReceived)
{
System.out.println("Your bill is paid successfully !!! with amount -> " + amount);
System.out.println("Thank you!");
// condition to break the loop
// if below condition missed then system goes in infinite loop
isCashReceived = false;
}
}
}package _3_Session._2_For_Loop;
public class _1_for_loop {
public static void main(String[] args) {
// To print 1 to 10 integer
// For loop
System.out.println("Values in from range 1 to 10 are ->");
for (int i = 1; i <= 10; i++) {
System.out.println(i);
}
System.out.println("-----------------------------");
// Example - Print only even numbers in between 1 to 20
System.out.println("Even numbers from 0 to 20 are ->");
for (int even = 0; even <= 20; even = even+2) {
System.out.println(even); // 0, 2,... 18, 20
}
System.out.println("-----------------------------");
// Example - Print only even numbers in between 1 to 20
// with an if condition
System.out.println("Even numbers from 0 to 20 using if condition are ->");
for (int j = 0; j <= 20; j++) { //0 1 2 3 4 .... 20
if (j % 2 == 0) {
System.out.println(j);
}
}
// use case - While working with an application
// To print all links on a page for loop is used
}
}package _3_Session._2_For_Loop;
public class _2_for_loop_pattern_printing {
public static void main(String[] args) {
// Print the following pattern
// *
// **
// ***
// ****
for(int i=1;i<=4;i++) // for printing columns
{
for(int j=1;j<=i;j++) // for printing rows
{
System.out.print("*");
}
System.out.println();
}
System.out.println("--------------------");
System.out.println();
// Print the following pattern
// ****
// ***
// **
// *
for(int i=1;i<=4;i++) // for printing columns
{
for(int j=4;j>=i;j--) // for printing rows
{
System.out.print("*");
}
System.out.println();
}
}
}package _3_Session._3_Do_While_Loop;
public class _1_do_while_loop {
public static void main(String[] args) {
// Do while loop is similar to while loop
// only with one difference as
// At least one time the do block get executed
System.out.println("Values from range 10 to 20 are ->");
int i = 10; // Start Point
do {
System.out.println(i);
i++;
}
while (i<=20); // condition
}
}Click here-Array In Java
package _4_Session._1_Array;
public class _1_Array_In_Java {
public static void main(String[] args) {
// Array are used to store the same kind of variable with a single name.
// Also to save similar data we don't have to maintain unnecessary different variables
// with different names.
// Example
int i = 10;
i = 20;
int j = 30;
//int k = 40;
System.out.println("Value of i is " + i);
System.out.println(i);
// the value of i is getting overridden
// here is a problem if I want to store 10 and 20 and don't want to maintain a new variable.
System.out.println("----------------------------------------------------");
// Ways of declaration for Array
// Example - 1
int[] q = new int[4];
int x[] = new int[3];
// or
int []y = new int[3];
// or
int z[] = {10,20,30};
// Here Index number starting from 0 to 2 and length of array is 3 i.e for 0 to 2
// Note - The "new" keyword is to create data space into an array and not like to create objects with new keyword.
x[0] = 10; // filling 10 int value at 0th index
x[1] = 20; // filling 20 int value at 1st index
x[2] = 50; // filling 50 int value at 2nd index
//x[3] = 99;
// Access the values from the array
System.out.println(x[2]); // O/P - 50 // accessing data from 2nd index form the array
//System.out.println(x[5]); // O/P - java.lang.ArrayIndexOutOfBoundsException as there is no such index for i array
System.out.println(x.length); // O/P - 3 the .length is a method used to calculate the length of an array.
System.out.println(x[1]+x[2]); // O/P - 70
// To print all/specific the values from array
for(int k=0; k<x.length; k++) // if we write k<=i.length then after printing 10 20 50 it will throw exception
// for(int k=0; k<=i.length()-1; k++) // can be used also
{
System.out.println(x[k]);
if(x[k]==20)
{
System.out.println("The value 20 found in the array at index no -> " + k);
}
}
System.out.println("----------------------------------------------------");
// Example - 2
double k1[] = new double[5];
k1[0] = 12.33;
k1[1] = 45.56;
// k1[2] = 45.56;
k1[3] = 50; // can be stored as double can store int // 50.00
k1[4] = 99.78;
//k1[7] = 66.45; // at this line compiler won�t show any error but it will throw a runtime exception when code is
//executed either we print the value or not in both conditions
System.out.println(k1[0]);
System.out.println(k1[2]); // O/P - 0.00 as we haven�t stored any value at 2nd index so default value is printed.
// System.out.println(k1[7]); // this will throw java.lang.ArrayIndexOutOfBoundsException
System.out.println("----------------------------------------------------");
// Example - 3
String browsers[] = new String[4];
browsers[0] = "chrome";
browsers[1] = "opera";
browsers[2] = "firefox";
//browsers[3] = "ie";
browsers[3] = "safari";
for(int row=0; row<browsers.length; row++)
{
System.out.println(browsers[row]);
if(browsers[row].equals("chrome"))
{
System.out.println("Launch chrome�...");
}
else if(browsers[row].equals("opera"))
{
System.out.println("Launch opera....");
}
else if(browsers[row].equals("firefox"))
{
System.out.println("Launch firefox....");
}
else if(browsers[row].equals("ie"))
{
System.out.println("Launch ie.....");
}
else
{
System.out.println("No browser matches, enter the correct value");
}
}
System.out.println("----------------------------------------------------");
// Summary of topic
// Exceptions in array comes? -> - ArrayIndexOutOfBoundException
// .length used to check the length of the array
// Array will store data in form of indexes
// Array can be declared in many types
// While comparing primitive data types in array use == operator and for not primitive data types comparison use .equals method
// Limitation of Arrays
// 1. Suppose we have to store some kind of data like student name information,
// employee name and we have to use an array then we have to either declare the array
// size more then extra memory allocation happens and vice versa.
// 2. Size of array is fixed once it's created so we use arraylist to overcome this problem
// 3. Similar kind of data has to be stored in Array - We can use Object Array or ArrayList,
// but still in object array the size is fixed.(Object is super class of all classes)
// 4. Object array or normal array is used in real time applications where the data size is fixed
// ex- days in week, months, dates in month. Object Array ex - Employee information with Name, DOB, EmpId, EmpDept
// 5. Garbage collector dont remove the excess space which is unused by the huge array sizes,
// Gc will only removes objects which are unused
System.out.println("----------------------------------------------------");
Object emp[] = new Object[5];
emp[0] = "Tom"; // name
emp[1] = 25; // age
emp[2] = 499; // salary in dollars
emp[3] = true; // resident of india
emp[4] = 'm'; // gender
for(int a=0; a<emp.length; a++)
{
System.out.println(emp[a]);
}
// In the above example
// it will print all information about the employee.
// What if the parameters like having a laptop, contract type, etc then again we have to increase the size of the array.
// So we can use these array and Object array where the parameters and size of data is permanent type or fixed type.
// Ex - days in a week, months,
// Number of branches of a company,
// departments of the companies,
// number of subjects in a semester,
// flat numbers in an apartment.
//Note -
// 1. if we don�t add the values in the array and try to print it then the default value of the data type will get printed.
// 2. New keyword in arrays is used to allocate memory not for creation of object (in array context).
}
}Click here-String Manipulation
package _4_Session._2_String_Manipulation;
public class _2_String_Methods {
public static void main(String[] args) {
//Notes -
// String is a class & is a non primitive data type in java
// Non primitive data types having some functions associated with it
// String stores values in terms of a collection of Characters with index values
System.out.println("\n---------------------------------\n");
// 1. Finding a length of an String
String str1 = "Hello Everyone Lets learn somthing about String";
System.out.println("The length of str1 string is : " + str1.length());
// Note - 1. length() - to calculate the length of String
// 2. length - is a keyword to calculate length of array
System.out.println("\n---------------------------------\n");
// 2. Find character at some specific index value
String str2 = "I am learning String in Java";
System.out.println("Character in string str2 at Second index value is : " + str2.charAt(2));
System.out.println(str2.length());
//System.out.println("Character in string str2 at 48th index is : " + str2.charAt(48));
System.out.println("\n---------------------------------\n");
// 3. Find index number of a specific character in string
String str3 = "Hello there";
System.out.println(str3.length());
System.out.println("Index number of character 'e' in String str3 is : " + str3.indexOf('e'));
System.out.println("Index number of character 'e' second occurence in String str3 is : " + str3.indexOf('e', 2));
System.out.println("Index number of character 'e' second occurence in String str3 is : " + str3.indexOf('e', str3.indexOf('e')+1)); // alternate way
System.out.println("Index number of character 'z' in string str3 is : " + str3.indexOf('z'));
System.out.println("\n---------------------------------\n");
// 4. Find start index of a specific word in a string
String str4 = "GitHub is aquired by microsoft in year 2018";
System.out.println("Index number for the word \"by\" in string str4 is : " + str4.indexOf("by"));
System.out.println("Index number for the word \"apple\" in string str4 is : " + str4.indexOf("apple"));
System.out.println("\n---------------------------------\n");
// 5. To convert all characters in a string into upper case
String str5 = "Selenium is used to automate web application";
System.out.println("Converting string str5 to uppercase : " + str5.toUpperCase());
System.out.println("\n---------------------------------\n");
// 6. To convert all characters in a string into upper case
String str6 = "SELENIUM CANNOt AUTOMATe DEXTOP APPLICATIONS";
System.out.println("Converting string str6 to uppercase : " + str6.toLowerCase());
System.out.println("\n---------------------------------\n");
// 7. To remove empty spaces present before and after from the string
String str7 = " Selenium is free automation tool ";
System.out.println("After removing extra spaces from before & after of String str7 output is :- " + str7.trim());
System.out.println("\n---------------------------------\n");
// 8. To remove some repeating specific character from the string
String str8 = "15/11/2012"; // 15:11:2012
System.out.println("After replacing the '/' to ':' str8 becomes " + str8.replace('/', ':'));
System.out.println("\n---------------------------------\n");
// 9. To check a specific word available in a string [with Case sensitivity]
String str9 = "Selenium can handle the html code";
System.out.println("The availibilty of word \"Selenium\" is : " + str9.contains("Selenium"));
System.out.println("\n---------------------------------\n");
// 10. To fetch a part from a string
String str10 = "The transation number is - 45AdSJ9t";
System.out.println("The transation number is : " + str10.substring(27));
System.out.println("\n---------------------------------\n");
// 11. To fetch a word from a string
String str11 = "Your transaction number is - 78E354dL thank you";
String TransationId = str11.substring(29, 37);
System.out.println("The extracted id from str11 is : " + TransationId);
System.out.println("\n---------------------------------\n");
// 12. To compare two strings
String statement1 = "Java is platform independent";
String statement2 = "java is platform independent";
String statement3 = "Java is platform independent";
System.out.println("Are statement1 & statement2 having exact same content : " + statement1.equals(statement2));
System.out.println("Are statement1 & statement3 having exact same content : " + statement1.equals(statement3));
System.out.println("Are statement1 & statement2 having exact same content : " + statement1.equalsIgnoreCase(statement2));
System.out.println("\n---------------------------------\n");
// 13. Splitting the String on basis of some specific char
String str13 = "Java is based on Object Oeriented Programming Principles";
String[] words = str13.split(" ");
for (int i = 0; i < words.length; i++) {
System.out.println(words[i]);
}
System.out.println("\n---------------------------------\n");
// 14. Splitting the String on basis of some specific char & print it in reverse order(Word by word)
String stm = "Good Bye";
String revWord[] = stm.split(" ");
System.out.println(revWord[1]+" "+revWord[0]); // O/P - "Bye Good"
}
}Click here-Object Array
package _5_Session._1_Object_Array;
public class _1_Object_Array {
public static void main(String[] args) {
// object static array:
Object emp[] = new Object[5];
emp[0] = "Tom"; // Name
emp[1] = 25; // Age
emp[2] = 10000; // Salary
emp[3] = 'm'; // gender
emp[4] = true; // Resident of India
System.out.println("Employee Imformation as below - ");
for (int m = 0; m < emp.length; m++) {
System.out.print(m+1 + ". ");
System.out.println(emp[m]);
}
System.out.println(emp[4]);
}
}
package _5_Session._2_Dynamic_Array;
import java.util.ArrayList;
public class _1_ArrayList_RawType {
public static void main(String[] args) {
ArrayList ar = new ArrayList(); // raw type arraylist, here any type of data can be stored
System.out.println("---------------------------");
System.out.println("Empty Arraylist Size is -> ");
System.out.println(ar.size()); // will print size of ArrayList which is 0
System.out.println("---------------------------");
System.out.println("Adding values 3 values in the empty arraylist");
ar.add(100); // 0th index
ar.add(200); // 1st index
ar.add("test"); // 2nd index
System.out.println("After adding 3 values checking the size of arraylist -> ");
System.out.println(ar.size()); // will print size of ArrayList which is 3
System.out.println("---------------------------");
System.out.println("Adding 2 more values in arraylist");
ar.add(500); // 3rd index
ar.add(800); // 4th index
System.out.println("After adding 2 more values checking the size of arraylist -> ");
System.out.println(ar.size()); // will print size of ArrayList which is 5
System.out.println("---------------------------");
System.out.println("Printing all values from the arraylist");
// To print all values of the ArrayList
for(int i=0; i<ar.size(); i++)
{
System.out.println(ar.get(i)); // this will print all the values currently an ArrayList is holding
}
System.out.println("---------------------------");
System.out.println("Accessing value form arraylist with specific index");
System.out.println(ar.get(2)); // will print the value of 2nd index value which is test
System.out.println("---------------------------");
System.out.println("Trying to access a value form arraylist more than its decleared size");
// System.out.println(ar.get(6)); // will throw exception java.lang.IndexOutOfBoundException as there is no value at 6th index
System.out.println("---------------------------");
System.out.println("Removing value form arraylist at a specific index and re-printing the values");
ar.remove(3); // this will remove the value from 3rd index
System.out.println("After removing the value from 3rd index the size of arraylist is -> " + ar.size());
for(int j=0; j<ar.size(); j++)
{
System.out.println(ar.get(j)); // this will print all the values currently an ArrayList is holding
}
System.out.println("---------------------------");
System.out.println("Checking a value is available in the arraylist");
// To check some values is present in ArrayList
for(int k=0; k<ar.size(); k++)
{
if (ar.get(k).equals("test"))
{
System.out.println("At index value " + k + " \"" + ar.get(k) + "\" is present");
}
}
}
}Click here-Dynamic Array-ArrayList Generic Type
package _5_Session._2_Dynamic_Array;
import java.util.ArrayList;
public class _2_ArrayList_GenricType {
public static void main(String[] args) {
// Arraylist of String Type
ArrayList<String> userNames = new ArrayList<String>();
userNames.add("Tom");
userNames.add("Peter");
userNames.add("Mark");
// userNames.add(45); // this line will throw an error at compile time
System.out.println("Printing the all values form arraylist");
for (int i = 0; i < userNames.size(); i++) {
System.out.println(userNames.get(i));
}
ArrayList<Integer> numberList = new ArrayList<Integer>();
numberList.add(10);
numberList.add(20);
numberList.add(30);
numberList.add(40);
// numberList.add("Fifty"); // this line will throw an error at compile time
System.out.println("Printing the all values form arraylist");
for (int i = 0; i < numberList.size(); i++) {
System.out.println(numberList.get(i));
}
}
}Click here-Dynamic Array Array List Object Type
package _5_Session._2_Dynamic_Array;
import java.util.ArrayList;
public class _3_ArrayList_ObjectType {
public static void main(String[] args) {
ArrayList<Object> employeeInf = new ArrayList<Object>();
employeeInf.add("Tom");
employeeInf.add('m');
employeeInf.add(499);
employeeInf.add(true);
System.out.println("----------------------");
System.out.println("After adding elements in the arraylist of Object type size is -> " + employeeInf.size());
// Printing all values of arraylist
System.out.println("Printing the all values form arraylist");
for (int i = 0; i < employeeInf.size(); i++) {
System.out.println(employeeInf.get(i));
}
System.out.println("----------------------");
// Removing all elements from the arraylist in one go
employeeInf.clear();
System.out.println("After using .clear() method on arraylist of Object type size is -> " + employeeInf.size());
}
}Click here-Data Conversion-Wrapper Class
package _5_Session._3_Data_Conversion;
public class _1_Wrapper_Classes {
public static void main(String[] args)
{
// To convert data from one data type to another
// 1. String to Integer
System.out.println("String to Integer");
String x = "100";
System.out.println(x+10); // 10010
int i = Integer.parseInt(x); // converting string to int
System.out.println(i+10); // 110
System.out.println("------------------");
// 2. Integer to String
System.out.println("Integer to String");
int q = 10;
System.out.println(q+5); // 15
String s = String.valueOf(q);
System.out.println(s+5); // 1015
System.out.println("------------------");
// 3. String to Double
System.out.println("String to Double");
String b = "12.33";
double d = Double.parseDouble(b); // Converting String to double
System.out.println(d+10.00);
System.out.println("------------------");
// Exmaple -
String g = "$156";
int h = Integer.parseInt(g); // it will throw NumberFormatException
System.out.println(h);
}
}Click here-Default Values
package _6_Session._1_Default_Values;
public class _1_DefaultValues
{
public static String str;
public static int i;
public static double d;
public static boolean b;
public static char c;
public static byte z;
public static void main(String[] args)
{
System.out.println(str);
System.out.println(i);
System.out.println(d);
System.out.println(b);
System.out.println(c);
System.out.println(z);
System.out.println("--------------------------------------");
//int p; // only variable declared without initialing value
//System.out.println(p); // this will show an error as the variable p is local to main method and
//value for it has to be declared.
int div1 = 9/3;
System.out.println(div1);
int div2 = 0/3;
System.out.println(div2);
//int div3 = 9/0;
//System.out.println(div3);
}
}Click here-Classes And Methods
package _6_Session._2_Classes_And_Methods;
public class _1_WebPage {
// 1. All the code we write in java is inside class.
// Class is a template where we write our logic, similar to the kind of
// things/logic we will write in the same class.
// 2. An object is an entity that comes from class.
// And when we create an object of this class we will have all the data members with each object.
String title = "Welcome to BestGoods";
String url = "https://www.bestgoods.com";
String header = "bestgoods.com: Online Shopping - Buy mobiles, laptops, cameras, books, "
+ "watches, apparel, shoes and e-Gift Cards. Free Shipping & Cash on Delivery Available.";
String logoImage = "https://www.bestgoods.com/images/logo";
// Non Static Methods
public void topPannel() {
// logic
System.out.println("---------------- topPannel Start ------------------");
System.out.println(url);
System.out.println("This is a top pannel of the webpage");
System.out.println(title);
System.out.println(logoImage);
System.out.println("----------------topPannel End ---------------------");
}
public void footerLinks() {
// logic
System.out.println("---------------- footerLinks Start ----------------");
System.out.println("Footer Link 1");
System.out.println("Footer Link 2");
System.out.println("Footer Link 3");
System.out.println("---------------- footerLinks End ------------------");
}
// Static methods
public void centerPannel() {
// logic
System.out.println("---------------- centerPannel Start ---------------");
System.out.println("Mobiles");
System.out.println("Laptop");
System.out.println("Books");
System.out.println("Camera");
System.out.println("---------------- centerPannel End -----------------");
}
public static void privacyPolicy() {
// logic
System.out.println("---------------- privacyPolicy Start --------------");
System.out.println("About BestGoods Business");
System.out.println("BestGoods Vendors");
System.out.println("Privacy Notice");
System.out.println("---------------- privacyPolicy End ----------------");
}
}package _6_Session._2_Classes_And_Methods;
public class _2_WebPageExecution {
public static void main(String[] args) {
// Creating the object of an _1_WebPage Class
_1_WebPage webpage = new _1_WebPage();
// Calling non static methods from _1_WebPage class for execution of the logic
webpage.topPannel();
webpage.footerLinks();
webpage.centerPannel();
//webpage.privacyPolicy();
// Calling static methods from _1_WebPage class for execution of the logic
_1_WebPage.privacyPolicy();
}
}package _6_Session._3_Different_Methods;
import java.util.ArrayList;
public class _1_System_Methods {
static String welcomeMessage = " Hello User Welcome ";
public static void main(String[] args) {
System.out.println("--- Checking the Size of welcome message String ---");
System.out.println("The Size is " + welcomeMessage.length());
// Here length() is a system defined method where its logic is predefined
System.out.println("---------------------------------------------------");
System.out.println("--- Triming white spaces of the welcome message ---");
System.out.println("After removal of white spaces the welcome message is ");
System.out.println(welcomeMessage.trim());
System.out.println("---------------------------------------------------");
ArrayList<Integer> multipleOfTen = new ArrayList<Integer>();
multipleOfTen.add(10); // this add method is defined in class ArrayList with its logic
multipleOfTen.add(20);
multipleOfTen.add(20);
multipleOfTen.add(30);
multipleOfTen.add(40);
multipleOfTen.remove(1); // Remove the duplicate value form index position 1 from ArrayList
System.out.println("Values of multiple of Ten are - ");
for (int i = 0; i < multipleOfTen.size(); i++) {
System.out.println(multipleOfTen.get(i));
// this get method is defined in class
// ArrayList with its logic
}
}
}package _6_Session._3_Different_Methods;
import jdk.nashorn.internal.runtime.regexp.joni.constants.OPCode;
public class _2_UserDefined_Methods {
// 1. No input no return method -
// it doesn't take any input and doesn't return anything
public void test()
{
System.out.println("test method");
}
// 2. No input some return function -
// this function doesn't take any input but return something
// Example 1
public String nameOfCountry()
{
String countryName = "India";
return countryName;
}
// Example 2
public String[] listOfStudents()
{
System.out.println("Student List - ");
String names[] = new String[3];
names[0] = "Tom";
names[1] = "Harry";
names[2] = "John";
return names;
}
// 3. Some input with some return
// Example 1
public int add(int a, int b)
{
int c = a+b;
return c;
}
// Example 2
public String factoryName(String NameOfFactory)
{
if (NameOfFactory.equals("nike")) {
String fact1 = "nike";
System.out.println("This is nike factory");
return fact1;
}
else if (NameOfFactory.equals("puma")) {
String fact2 = "puma";
System.out.println("This is puma factory");
return fact2;
}
return "no factory within the criteria found";
}
// Example 3
public String countryCapital(String NameOfCountry) {
if (NameOfCountry.equals("india")) {
return "New Delhi";
}
if (NameOfCountry.equals("usa")) {
return "Washington DC";
} else {
return "no country found";
}
}
// Calling above user defined methods to execute the actual logic
public static void main(String[] args) {
_2_UserDefined_Methods userDefMethods = new _2_UserDefined_Methods();
System.out.println("----------------------------------------------");
// Calling Test Method
userDefMethods.test();
System.out.println("----------------------------------------------");
// Calling nameOfCountry method
// First Way
String countryName = userDefMethods.nameOfCountry();
System.out.println("The country name is - " + countryName);
// Second Way
System.out.println("The country name is - " + userDefMethods.nameOfCountry());
System.out.println("----------------------------------------------");
// Calling listOfStudents method
String[] listOfStd = userDefMethods.listOfStudents();
for (int i = 0; i < listOfStd.length; i++) {
System.out.println((i+1) + " " + listOfStd[i]);
}
System.out.println("----------------------------------------------");
// Calling add method
int total = userDefMethods.add(10, 30);
System.out.println("The total is -> " + total);
System.out.println("----------------------------------------------");
// Calling factoryName method
String outputFromFarctory = userDefMethods.factoryName("nike");
System.out.println(outputFromFarctory);
System.out.println("----------------------------------------------");
// Calling countryCapital method
String countryCap = userDefMethods.countryCapital("india");
System.out.println(countryCap);
System.out.println("----------------------------------------------");
}
}package _6_Session._3_Different_Methods;
import java.util.Scanner;
public class _3_Input_From_User_1 {
public static void main(String[] args) {
System.out.println("Please enter the factory name");
Scanner sc = new Scanner(System.in);
String userInput = sc.next();
sc.close();
_2_UserDefined_Methods userMethods = new _2_UserDefined_Methods();
String outputFromFarctory = userMethods.factoryName(userInput);
System.out.println(outputFromFarctory);
}
}package _6_Session._3_Different_Methods;
import java.util.Scanner;
public class _3_Input_From_User_2 {
public static void main(String[] args) {
System.out.println("Please enter the country name");
Scanner sc = new Scanner(System.in);
String userInput = sc.next();
sc.close();
_2_UserDefined_Methods userMethods = new _2_UserDefined_Methods();
String countryNameIs = userMethods.countryCapital(userInput);
System.out.println(countryNameIs);
}
}package _6_Session._3_Different_Methods;
import java.util.Scanner;
public class _3_Input_From_User_3 {
public static void main(String[] args) {
System.out.println("Please enter the two numbers for total");
Scanner sc = new Scanner(System.in);
int intOne = sc.nextInt();
int intTwo = sc.nextInt();
sc.close();
_2_UserDefined_Methods userMethods = new _2_UserDefined_Methods();
int totalOfNumbers = userMethods.add(intOne, intTwo);
System.out.println("The total for two numbers " + intOne + " & " + intTwo + " is -> ");
System.out.println(totalOfNumbers);
}
}Click here-Static and Non Static
package _7_Session._1_Static_And_NonStatic;
public class _1_StaticAndNonStaticConcept {
String name;
static int age = 25;
public void getName() {
System.out.println("get name");
}
public static void getStart() {
System.out.println("get start");
}
public static void main(String[] args) {
// 1. how to call static data members: variables and methods
// no need to create the object
// a. call them directly
System.out.println("1.-------------- Calling Static Data Members without creation object -------------------");
getStart();
System.out.println(age);
System.out.println("----------------------------------------------------------------------------------------");
// b. call them by class name:
System.out.println("2.-------- Calling Static Data Members without creation object with class name ---------");
_1_StaticAndNonStaticConcept.getStart();
System.out.println(_1_StaticAndNonStaticConcept.age);
System.out.println("----------------------------------------------------------------------------------------");
// 2. how to call non static data members: variables and methods:
// you have to create the object
System.out.println("3.---------------- Calling Non Static Data Members with creation object ----------------");
_1_StaticAndNonStaticConcept obj = new _1_StaticAndNonStaticConcept();
obj.getName();
obj.name = "Steve";
System.out.println(obj.name);
System.out.println("----------------------------------------------------------------------------------------");
// Question: can i access static variables and methods by object:
System.out.println("4.----------------- Calling Static Data Members with obj refernece --------------------");
obj.getStart();
System.out.println(obj.age);
System.out.println("----------------------------------------------------------------------------------------");
//can I create the object wihout any reference?
System.out.println("5.----------- Creating an object without object reference and calling method -----------");
new _1_StaticAndNonStaticConcept().getName();
System.out.println(new _1_StaticAndNonStaticConcept().name = "Tom");
System.out.println("----------------------------------------------------------------------------------------");
System.out.println("6.----------- Creating an object And making its reference null ------------- -----------");
_1_StaticAndNonStaticConcept obj1 = new _1_StaticAndNonStaticConcept();
//obj1.getName();
//obj1=null;
//obj1.getName(); // this line will throw java.lang.NullPointerException exception
}
}package _7_Session._1_Static_And_NonStatic;
public class _2_Car {
// Below Data members are subject to change for every car so declared as non static
String name;
int price;
String colour;
// As wheels is an constant entity for a car so declared as static
static int wheels = 4;
public static void main(String[] args)
{
System.out.println("Sports Car Details ---- ");
_2_Car sportsCar = new _2_Car();
// assigning the values for the sportsCar
sportsCar.name = "BMW";
sportsCar.price = 40_000;
sportsCar.colour = "Sterling Black";
sportsCar.wheels = 5;
// variables value
System.out.println("---- sports Car Details ----");
System.out.println(sportsCar.name);
System.out.println(sportsCar.colour);
System.out.println(sportsCar.price);
// System.out.println(sportsCar.wheels); // avoid using this and use for static data members
System.out.println(wheels);
System.out.println("----------------------------");
// assigning the values for the sportsCar
_2_Car passengerCar = new _2_Car();
passengerCar.name = "WagonR";
passengerCar.price = 6_000;
passengerCar.colour = "White";
System.out.println("-- Passenger Car Details ---");
System.out.println(passengerCar.name);
System.out.println(passengerCar.colour);
System.out.println(passengerCar.price);
// System.out.println(passengerCar.wheels); // avoid using this and use for static data members
System.out.println(wheels);
System.out.println("----------------------------");
}
}package _7_Session._1_Static_And_NonStatic;
public class _3_WebApplicationPages {
// data members of the class: class vars, class methods
String title;
String url;
String header;
static String logo = "http://www.aws3.amazon.com/images/logo.png";
public void topPanel() {
System.out.println("Top panel");
}
public void leftPanel() {
System.out.println("leftPanel");
}
public void footerLinks() {
System.out.println("footerLinks");
}
public static void privacyPolicy() {
System.out.println("privacyPolicy");
}
public static void main(String[] args) {
_3_WebApplicationPages p1 = new _3_WebApplicationPages();
_3_WebApplicationPages p2 = new _3_WebApplicationPages();
_3_WebApplicationPages p3 = new _3_WebApplicationPages();
// Assigning the values for Login page
p1.title = "LoginPage";
p1.header = "Login to app";
p1.url = "http://abc.com/login";
System.out.println("-----------------------------------------------");
// Assigning the values for Home page
p2.title = "HomePage";
p2.header = "Welcome to Home Page";
p2.url = "http://abc.com/home";
System.out.println("------------- WebPage for Login --------------");
System.out.println(p1.title + " | " + p1.header + " | " + p1.url);
p1.leftPanel();
p1.topPanel();
p1.footerLinks();
System.out.println("Logo -> "+_3_WebApplicationPages.logo);
_3_WebApplicationPages.privacyPolicy();
System.out.println("----------------------------------------------");
System.out.println("---------- WebPage for after login -----------");
System.out.println(p2.title + " | " + p2.header + " | " + p2.url);
p2.leftPanel();
p2.topPanel();
p2.footerLinks();
System.out.println("Logo -> "+_3_WebApplicationPages.logo);
_3_WebApplicationPages.privacyPolicy();
System.out.println("----------------------------------------------");
//System.out.println(p3.header); // This will print default String value as null
System.out.println("----------------------------------------------");
}
}Click here-Overloading
package _7_Session._2_Overloading;
public class _1_LoginToApplication {
// Overloading - Why? -> To avoid unnecessary creation of different method for same
// functionality & minimize the confusion while calling the methods
// Means - The method signature should be different with a similar name.
// Note - Method overloading has nothing to do with the internal logic of the overloaded methods
// Overloading means - within class, when we have different methods with same name
// but
// 1. different number of parameters
// 2. types (Data types)
// 3. sequence of parameters
public void login(){
System.out.println("login 0 param method");
}
public void login(String username){
System.out.println("login 1 parameters method -> Username");
}
public void login(int OTP){
System.out.println("login 1 parameters method -> OTP");
}
public void login(String username, String password){
System.out.println("login 2 parameters method -> Username & Password");
}
public void login(long phoneNumber, String password){
System.out.println("login 2 parameters method -> Phone Number & Password");
}
public void login(String username, long phoneNumber){
System.out.println("login 2 parameters method -> Username & Phone Number");
}
// This is a duplicate method
// public void login(String emailid, long OTP){
// System.out.println("login 2 parameters method -> emailId & OTP");
// }
public static void main(String[] args) {
_1_LoginToApplication lp = new _1_LoginToApplication();
lp.login();
lp.login(3453);
lp.login("John");
lp.login("john", "john@123");
lp.login(746256454, "john@123");
lp.login("john", 746256454);
}
}package _7_Session._2_Overloading;
public class _2_SearchProduct {
public void search(String product) {
System.out.println("Product Search with Product Name");
}
public void search(String product, int price) {
System.out.println("Product Search with Product Name and Price");
}
public void search(String product, int price, String seller) {
System.out.println("Product Search with Product Name, Price and Seller Name");
}
public void payment(long CCNumber) {
System.out.println("Payment With Credit Card Number");
}
public void payment(long CCNumber, int pin) {
System.out.println("Payment With Credit Card Number and Pin");
}
public void payment(long CCNumber, int pin, String cardHolderName) {
System.out.println("Payment With Credit Card Number, Pin and Card Holder Name");
}
public static void main(String[] args) {
System.out.println("------------------------------------");
_2_SearchProduct productSearch = new _2_SearchProduct();
productSearch.search("Laptop");
productSearch.search("Laptop", 500);
productSearch.search("Laptop", 500, "Unicorn Enterprise");
System.out.println("------------------------------------");
_2_SearchProduct makePayment = new _2_SearchProduct();
makePayment.payment(451245565);
makePayment.payment(451245565, 4589);
makePayment.payment(451245565, 4589, "Tom Peter");
System.out.println("------------------------------------");
}
}package _7_Session._2_Overloading;
public class _3_Book_a_Car {
public void getCar() {
System.out.println("Booking a car");
}
public void getCar(String carType) {
System.out.println("Booking a " +carType+ " car");
}
public void getCar(String carType, int seater) {
System.out.println("Booking a " +carType+ " car" + " with seating capacity of " +seater+ " people");
}
public static void main(String[] args) {
System.out.println("-------------------------------------------------------------------------------------------");
_3_Book_a_Car bookCar = new _3_Book_a_Car();
System.out.println("-------------------------- Booking a car with system defined type -------------------------");
bookCar.getCar();
System.out.println("--------------------- Booking a car with specific defined type by user --------------------");
bookCar.getCar("Sedan");
System.out.println("---- Booking a car with specific defined type by user with passenger seating capacity -----");
bookCar.getCar("SUV", 7);
System.out.println("-------------------------------------------------------------------------------------------");
}
}package _7_Session._2_Overloading;
public class _4_Overload_Main_Method {
public static void main(String []a) {
System.out.println("Hey");
main(10);
main(10, 20);
}
public static void main(int p) {
System.out.println("Hey hi " + p);
}
public static void main(int p, int q) {
System.out.println("Hey bye" + p + q);
}
}package _7_Session._2_Overloading;
public class _5_A {
public static void main(String[] args) {
System.out.println("A main method");
_6_B.main(args);
}
}package _7_Session._2_Overloading;
public class _6_B {
public static void main(String[] args) {
System.out.println("B main method");
_5_A.main(args);
}
}package _7_Session._3_ReturnClassObjectByMethod;
public class _1_SignInPage {
public _2_HomePage login(String un, String pwd){
System.out.println("username is "+ un);
System.out.println("password is "+ pwd);
System.out.println("click on login button");
//return class object - home page class object from login() method
// 1.
return new _2_HomePage();
// 2.
//HomePage hp = new _2_HomePage();
//return hp;
}
}package _7_Session._3_ReturnClassObjectByMethod;
public class _2_HomePage {
public static void main(String[] args) {
_1_SignInPage sip = new _1_SignInPage();
_2_HomePage hp1 = sip.login("Tom", "test123");
hp1.searchProduct("cellphone");
hp1.addToCartProduct();
}
public void searchProduct(String productName)
{
System.out.println("Searching product in the inventory as " + productName + " .......");
}
public void addToCartProduct()
{
System.out.println("Adding product to the cart ...........");
}
}Click here-Constructors
package _8_Session._1_Constructors._1_WithoutConstructor;
public class _1_Employee {
// class variables:
String name;
int age;
String dept;
int empId;
static String compName = "Unicorn Systems";
public static void main(String[] args) {
// Assigning the values of class variables to the different object
// for employee e1 and e2
_1_Employee e1 = new _1_Employee();
e1.name = "Tom";
e1.age = 25;
e1.dept = "QA";
e1.empId = 101;
_1_Employee e2 = new _1_Employee();
e2.name = "Steve";
e2.age = 30;
e2.dept = "HR";
e2.empId = 102;
// Accessing the assigned values of the employee e1 and e2
System.out.println("Employee e1 details are -> ");
System.out.println("Name: " + e1.name);
System.out.println("Age: " + e1.age);
System.out.println("Department: " + e1.dept);
System.out.println("Employee ID: " + e1.empId);
System.out.println("---------------------------");
System.out.println("Employee e2 details are -> ");
System.out.println("Name: " + e2.name);
System.out.println("Age: " + e2.age);
System.out.println("Department: " + e2.dept);
System.out.println("Employee ID: " + e2.empId);
System.out.println("---------------------------");
}
}
package _8_Session._1_Constructors._2_WithConstructor;
public class _1_Employee {
// class vars:
String name;
int age;
String dept;
int empId;
static String compName = "Unicorn Systems";
// Constructors is the mechanism called when an object of a class got created
// Points to be noted - 1. It has no return type
// 2. It has same name of the class name
// 3. If no constructor is provided by user java creates it
// 4. Types of constructors: 1. User defined Default constructor
// 2. User defined constructor (parameterized or non parameterized)
// 5. Constructor can be overloaded with different parameters
public _1_Employee() // 0 parameter
{
System.out.println("default const...");
}
public _1_Employee(int i) // 1 parameter integer type
{
System.out.println("one param const..." + i);
}
public _1_Employee(String s) // 1 parameter String type
{
System.out.println("one param const..." + s);
}
// create parameterized constructor with all class variables initialized
public _1_Employee(String name, int age, String dept, int empId) {
// name = name; // this line has no effect
this.name = name;
this.age = age;
this.dept = dept;
this.empId = empId;
}
// created parameterized constructor with only two class variables initialized
public _1_Employee(String name, int empId) {
this.name = name;
this.empId = empId;
}
public static void main(String[] args) {
System.out.println("Calling zero pparameter constructor");
_1_Employee e0 = new _1_Employee();
System.out.println("-----------------------------------");
System.out.println("Calling One pparameter constructor int type");
_1_Employee e1 = new _1_Employee(10);
System.out.println("-----------------------------------");
System.out.println("Calling One pparameter constructor String type");
_1_Employee e2 = new _1_Employee("Thomas");
System.out.println("-----------------------------------");
_1_Employee e3 = new _1_Employee("Jeff", 35, "Admin", 102);
_1_Employee e4 = new _1_Employee("Harry", 25, "QA", 103);
_1_Employee e5 = new _1_Employee("Louis", 45, "Dev", 104);
System.out.println("-----------------------------------");
System.out.println(e3.name + " " + e3.age + " " + e3.dept + " " + e3.empId + " " + _1_Employee.compName);
System.out.println(e4.name + " " + e4.age + " " + e4.dept + " " + e4.empId + " " + _1_Employee.compName);
System.out.println(e5.name + " " + e5.age + " " + e5.dept + " " + e5.empId + " " + _1_Employee.compName);
System.out.println("-----------------------------------");
}
}package _8_Session._1_Constructors._2_WithConstructor;
public class _2_RegistrationPage {
String firstName; // Mandatory filed
String lastName; // Mandatory filed
long phoneNumber; // Mandatory filed
String emailId; // Mandatory filed
String password; // Mandatory filed
String address; // Non mandatory filed
String dob; // Non mandatory filed
String dlNumber; // Non mandatory filed
String gender; // Non mandatory filed
boolean agelimit; // Non mandatory filed
int otp; // Mandatory filed
public _2_RegistrationPage() {
System.out.println("Please pass some values...");
}
// with Mandatory + Non Mandatory fields
public _2_RegistrationPage(String firstName, String lastName, long phoneNumber, String emailId, String password,
String address, String dob, String dlNumber, String gender, boolean agelimit, int otp) {
this.firstName = firstName;
this.lastName = lastName;
this.phoneNumber = phoneNumber;
this.emailId = emailId;
this.password = password;
this.address = address;
this.dob = dob;
this.dlNumber = dlNumber;
this.gender = gender;
this.agelimit = agelimit;
this.otp = otp;
}
// with Mandatory only fields
public _2_RegistrationPage(String firstName, String lastName, long phoneNumber, String emailId, String password,
int otp) {
this.firstName = firstName;
this.lastName = lastName;
this.phoneNumber = phoneNumber;
this.emailId = emailId;
this.password = password;
this.otp = otp;
}
public void doRegistrationWithAllFields() {
System.out.println("processing registration with.....\n " + firstName + " and " + lastName + " and " + phoneNumber);
System.out.println(" " + password + " and " + address + " and " + dob);
System.out.println(" " + dlNumber + " and " + gender + " and " + agelimit);
System.out.println(" " + otp);
}
public void doRegistrationWithMindatoryFileds() {
System.out.println("processing registration with.....\n " + firstName + " and " + lastName + " and " + phoneNumber);
System.out.println(" " + emailId + " and " + password + " and " + otp);
}
public void getOTP(){
System.out.println(otp);
}
}package _8_Session._1_Constructors._2_WithConstructor;
public class _3_RegistrationTest {
public static void main(String[] args) {
_2_RegistrationPage reg = new _2_RegistrationPage();
// Registering user with all fields
_2_RegistrationPage reg1 = new _2_RegistrationPage("Harry", "Joe", 89564556, "[email protected]",
"123@Abc", "18, Hollywood Ave, LA", "01-01-1987", "LA-101-9090", "male", true, 8956);
// Registering user with only mandatory fields
_2_RegistrationPage reg2 = new _2_RegistrationPage("Jonny", "Mathew", 45784556, "[email protected]", "123@Abc", 4578);
System.out.println("-------------------------------------");
reg1.doRegistrationWithAllFields();
System.out.println("-------------------------------------");
reg2.doRegistrationWithMindatoryFileds();
System.out.println("-------------------------------------");
}
}Click here-Inheritance
package _8_Session._2_Inheritance;
public class _0_Vehicle {
public void engine(){
System.out.println("Vehicle -- Engine");
}
}package _8_Session._2_Inheritance;
public class _1_Car extends _0_Vehicle{
public void start() {
System.out.println("Car -- start");
}
public void stop() {
System.out.println("Car -- stop");
}
public void fillFuel() {
System.out.println("Car -- fuel");
}
}package _8_Session._2_Inheritance;
public class _2_BMW extends _1_Car {
//A method in parent class as well as in child class with the same name & same no of parameters -
//method overriding
@Override
public void start() {
// Something like advance feature - key less entry & Button Start
System.out.println("BMW -- start");
}
// @Override
// public void start(int a) {
// System.out.println("BMW -- start");
// }
//@Override
public void autoParking() {
System.out.println("BMW -- auto parking");
}
}package _8_Session._2_Inheritance;
public class _3_TestCar {
public static void main(String[] args) {
System.out.println("---------------------------------------------");
System.out.println("Child class reference with child class object");
_2_BMW b = new _2_BMW();
b.stop(); // calls Car class stop method
b.start(); // calls BMW class start Method
b.fillFuel(); // calls Car class stop method
b.autoParking(); // calls BMW class autoParking Method
b.engine(); // calls Vehicle class engine Method
System.out.println("---------------------------------------------");
System.out.println("Parent class reference with parent class object");
_1_Car c = new _1_Car();
c.start(); // calls Car class start method
c.stop(); // calls Car class stop method
c.fillFuel(); // calls Car class fillFuel method
c.engine(); // calls Vehicle class engine Method
//c.autoParking(); // Parent cannot inherit the property from child class
System.out.println("---------------------------------------------");
System.out.println("Parent class reference with child class object");
//Top Casting/ Up casting
_1_Car c1 = new _2_BMW();//child class object can be referred by parent class ref variable...
c1.start(); // calls Car class start method
c1.stop(); // calls Car class stop method
c1.fillFuel(); // calls Car class fillFuel method
//c1.autoParking(); // this cannot be accessed as autoParking method is not available in Car class
System.out.println("---------------------------------------------");
System.out.println("Grand Parent class reference with child class object");
_0_Vehicle v1 = new _2_BMW();
v1.engine(); //calls Vehicle class engine Method
System.out.println("---------------------------------------------");
//Down Casting
//_2_BMW b1 = (_2_BMW) new _1_Car(); //ClassCastException as every car cannot be BMW, so its not allowed at runtime
// Noted -
// Polymorphism - Many forms - In Java achieved in terms of overloading and overriding
// Static methods cannot be overridden (as objects cannot hold any static properties of a class)
// Method declared as final cannot be overridden (Used to prevent inheritance)
// A class declared as final cannot be extended (Used to prevent inheritance)
}
}Click here-Abstraction
package _9_Session._1_Abstraction._1_By_Interface;
public interface _0_WHO {
public void polioServices();
}package _9_Session._1_Abstraction._1_By_Interface;
public interface _1_USMedical extends _0_WHO {
int min_fee = 10; // By default the variables are static as well as final
public void physioServices(); // Abstract(Prototype) method
public void oncologyServices(); // Abstract(Prototype) method
public void orthopedicServices(); // Abstract(Prototype) method
public void RadioLogyServices(); // Abstract(Prototype) method [Common service also available in other interfaces]
//can not create the object of Interface
//only method declaration -- method prototype -- no method body -- Abstract Methods
//can not create static Abstract(prototype) method in Interface - because we cannot override static methods
//Example
//public static void testServices();
//Interface variables are static and final by default
//From JDK1.8, you can have static methods in interface but with method body
//static method with method body:
public static void Services_911(){
System.out.println("US - 911 services....");
}
// default method cannot be overridden
default void intership(){
System.out.println("US - intership....");
}
}package _9_Session._1_Abstraction._1_By_Interface;
public interface _2_UKMedical extends _0_WHO {
public void ENTServices(); // Abstract(Prototype) method
public void ambulanceServices(); // Abstract(Prototype) method
public void RadioLogyServices(); // Abstract(Prototype) method [Common service also available in other interfaces]
}package _9_Session._1_Abstraction._1_By_Interface;
public interface _3_IndianMedical extends _0_WHO {
public void emegergencyServices(); // Abstract(Prototype) method
public void neuroServices(); // Abstract(Prototype) method
public void peditricServices(); // Abstract(Prototype) method
public void RadioLogyServices(); // Abstract(Prototype) method [Common service also available in other interfaces]
public static void dengueServices(){
System.out.println("Indian --- dengueServices");
}
}package _9_Session._1_Abstraction._1_By_Interface;
public class _4_ApolloHospital extends GlobalPatientData implements _1_USMedical, _2_UKMedical, _3_IndianMedical {
@Override
public void physioServices() {
System.out.println("Apollo - physio");
}
@Override
public void oncologyServices() {
System.out.println("Apollo - Oncology");
}
@Override
public void orthopedicServices() {
System.out.println("Apollo - orthopedic");
}
@Override
public void RadioLogyServices() {
System.out.println("Apollo - RadioLogyServices");
}
@Override
public void ENTServices() {
System.out.println("Apollo - ENTServices");
}
@Override
public void ambulanceServices() {
System.out.println("Apollo - ambulanceServices");
}
@Override
public void emegergencyServices() {
System.out.println("Apollo - emegergencyServices");
}
@Override
public void neuroServices() {
System.out.println("Apollo - neuroServices");
}
@Override
public void peditricServices() {
System.out.println("Apollo - peditricServices");
}
// From WHO Interface
@Override
public void polioServices() {
System.out.println("Apollo - polioServices");
}
// non overridden methods: (Specialized methods of ApolloHospital)
public void OPServices() {
System.out.println("Apollo - OPTServices");
}
public void medicalInsurance() {
System.out.println("Apollo - medicalInsurance");
}
public void pathalogyServices() {
System.out.println("Apollo - pathalogyServices");
}
}package _9_Session._1_Abstraction._1_By_Interface;
public class GlobalPatientData {
public void getPatientHistory() {
System.out.println("GlobalPatientData -- getPatientHistory");
}
public void RadioLogyServices()
{
System.out.println("RadioLogyServices");
}
}package _9_Session._1_Abstraction._1_By_Interface;
public class TestHospital {
public static void main(String[] args) {
// _1_USMedical usHp = new _1_USMedical(); // Not allowed as object of an interface cannot be created
_4_ApolloHospital ap = new _4_ApolloHospital();
ap.ambulanceServices(); // Apollo - ambulanceServices - from UKMedical Interface
ap.emegergencyServices(); // Apollo - emegergencyServices - from IndianMedical Interface
ap.ENTServices(); // Apollo - ENTServices - from UKMedical Interface
ap.medicalInsurance(); // Apollo - medicalInsurance - from ApolloHosptial Class
ap.neuroServices(); // Apollo - neuroServices - from IndianMedical Interface
ap.orthopedicServices(); // Apollo - ambulanceServices - from UKMedical Interface
System.out.println(ap.min_fee); // warning - from USMedical Interface
System.out.println(_1_USMedical.min_fee);
//_1_USMedical.min_fee = 20; // not allowed as the variable is final
_1_USMedical.Services_911(); // Static method - from USMedical Interface
ap.intership(); // default method - from USMedical Interface
ap.getPatientHistory(); // from GlobalPatientData Class
//top Casting:
_1_USMedical us = new _4_ApolloHospital();//child class object can be referred by parent interface reference variable
us.physioServices();
us.oncologyServices();
us.orthopedicServices();
us.intership();
//down Casting:
// its not allowed
// As object of a interface cannot be created
_2_UKMedical uk = new _4_ApolloHospital();
uk.ambulanceServices();
uk.ENTServices();
}
}package _9_Session._1_Abstraction._2_By_AbstractClass;
public abstract class _1_Page {
// Ques - Can abstract class be final
// Ans - No, a class can be either abstract or final not both
public _1_Page() {
System.out.println("Page Const.....");
}
public abstract void title(); // abstract method
public abstract void url(); // abstract method
public abstract void footerLinks(); //abstract method
public void logo() // Non abstract method
{
System.out.println("Page -- logo");
}
public final void privacyPolicy() // Non abstract final method - to avoid overriding the method
{
System.out.println("Page -- privacyPolicy");
}
// partial abstraction -- 0 to 100% abstraction with Abstract Class
// Full abstraction -- 100% abstraction with Interface
}package _9_Session._1_Abstraction._2_By_AbstractClass;
public class _2_LoginPage extends _1_Page{
public _2_LoginPage(){
System.out.println("Login page const...");
}
@Override
public void title() {
System.out.println("login page title");
}
@Override
public void url() {
System.out.println("http://google.com");
}
@Override
public void footerLinks() {
System.out.println("privacy policy");
}
@Override
public void logo(){
System.out.println("LoginPage -- logo");
}
// @Override
// public void privacyPolicy()
// {
// System.out.println("fvdf");
// }
// Special method of login page class
public void doLogin(){
System.out.println("login to app...");
}
}package _9_Session._1_Abstraction._2_By_AbstractClass;
public class _3_TestPage {
public static void main(String[] args) {
System.out.println("------------------------------");
_2_LoginPage lp = new _2_LoginPage();
lp.title(); // overridden method from abstract class
lp.url(); // overridden method from abstract class
lp.footerLinks(); // overridden method from abstract class
lp.doLogin(); // special method from login page class
lp.logo(); // Non abstract method from abstract class
lp.privacyPolicy(); // Non abstract final method from abstract class
System.out.println("------------------------------");
_1_Page p = new _2_LoginPage();
p.title(); // overridden method from abstract class
p.logo(); // Non abstract method from abstract class
p.privacyPolicy(); // Non abstract final method from abstract class
// p.doLogin(); // Not allowed - special method from login page class
System.out.println("------------------------------");
}
}Click here-Encapsulation
package _9_Session._2_Encapsulation;
public class _1_Company {
public String name;
public String logo;
public int EmpCount;
private String searchEngine;
private int revenue;
// getter and setter:
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getLogo() {
return logo;
}
public void setLogo(String logo) {
this.logo = logo;
}
public int getEmpCount() {
return EmpCount;
}
public void setEmpCount(int empCount) {
EmpCount = empCount;
}
public String getEngine() {
return searchEngine;
}
public void setEngine(String searchEngine) {
this.searchEngine = searchEngine;
}
public int getRevenue() {
return revenue;
}
public void setRevenue(int revenue) {
this.revenue = revenue;
}
}package _9_Session._2_Encapsulation;
public class _2_TestCompany {
public static void main(String[] args) {
_1_Company comp = new _1_Company();
System.out.println(comp.name);
System.out.println(comp.EmpCount);
System.out.println(comp.logo);
comp.setEngine("google");
System.out.println(comp.getEngine());
comp.setEmpCount(1000);
System.out.println(comp.getEmpCount());
}
}package _9_Session._2_Encapsulation;
public class _3_WebAutomation {
public void launchBrowser() {
interactWithBrowser();
}
private void interactWithBrowser() {
checkBrowserCompatibility();
}
private void checkBrowserCompatibility() {
checkBrowserVersion();
}
private void checkBrowserVersion() {
checkBrowserWithOS();
}
private void checkBrowserWithOS() {
System.out.println("launching the browser......");
}
}package _9_Session._2_Encapsulation;
public class _4_TestAutomation {
public static void main(String[] args) {
_3_WebAutomation web = new _3_WebAutomation();
web.launchBrowser();
}
}Click here-Inheritance
Click here-Exception Handling
- Exception - It is unpected situation where java is unable to proceed with the code.
- And the further flow of the program breaks down
- Expample -
- Any value divided by zero
- Accessing any value out of the range of an array
- Exception Handling - To do make the execution of a program uninterrupted, we should handle the exception.
- Errors - It indicate serious problems and abnormal conditions that most applications should not try to handle.
- Error defines problems that are not expected to be caught under normal circumstances by our program.
- For example memory error, hardware error, JVM error etc.
package _10_Session._1_TryCatchBlock;
public class _1_TryCatch {
public static void main(String[] args) {
System.out.println("A");
System.out.println("B");
System.out.println("C");
int a = 9/0; // this line will throw an exception which need to be handled
System.out.println("D");
System.out.println("E");
System.out.println("F");
//-------------------------------------------------------------------------------------
// System.out.println("A");
// System.out.println("B");
// System.out.println("C");
//
// try
// {
// int a = 9/0; // this line will throw an exception which need to be handled
// }
// catch (Exception e)
// {
// // TODO: handle exception
// }
//
// System.out.println("D");
// System.out.println("E");
// System.out.println("F");
//-------------------------------------------------------------------------------------
// System.out.println("A");
// System.out.println("B");
// System.out.println("C");
//
// try
// {
// int a = 9/0; // this line will throw an exception which need to be handled
// }
// catch (Exception e) // e is just a reference variable name for exception, can even write other variable name also
// {
// e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
// System.out.println("An Exception occured at division of integer a"); // User defined message for more clarification
// }
//
// System.out.println("D");
// System.out.println("E");
// System.out.println("F");
//
}
}package _10_Session._1_TryCatchBlock;
public class _2_TryCatch {
public static void main(String[] args) {
System.out.println("A");
System.out.println("B");
System.out.println("C");
try
{
int a = 9/0; // this line will throw an exception which need to be handled
}
catch (Throwable e) // Can mention throwable also as its a parent class of the all exceptions
{
e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
System.out.println("An Exception occured at division of integer a"); // User defined message for more clarification
}
System.out.println("D");
System.out.println("E");
System.out.println("F");
//-------------------------------------------------------------------------------------
// System.out.println("A");
// System.out.println("B");
// System.out.println("C");
//
// try
// {
// int a = 9/0; // this line will throw an exception which need to be handled
// }
// catch (NullPointerException e) // Proper exception name should be given else it will throw an exception
// {
// e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
// System.out.println("An Exception occured at division of integer a"); // User defined message for more clarification
// }
//
// System.out.println("D");
// System.out.println("E");
// System.out.println("F");
}
}package _10_Session._1_TryCatchBlock;
public class _3_TryCatch {
public static void main(String[] args) {
_3_TryCatch tc = new _3_TryCatch();
// Handling exception at method calling level
try
{
tc.division(9, 0);
}
catch (Exception e)
{
e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
System.out.println("An Exception occured at division of integer a"); // User defined message for more clarification
}
}
public void division(int a, int b)
{
int c = a/b;
System.out.println("The division of input " + a + " and" + b + " is -> " + c);
}
//-------------------------------------------------------------------------------------
// public static void main(String[] args) {
//
// _3_TryCatch tc = new _3_TryCatch();
//
// tc.division(9, 0);
//
// }
//
// public void division(int a, int b)
// {
//
// // Handling exception inside method
//
// try
// {
// int c = a/b;
// System.out.println("The division of input " + a + " and" + b + " is -> " + c);
// }
// catch (Exception e)
// {
// e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
// System.out.println("An Exception occured inside division method"); // User defined message for more clarification
// }
// }
}package _10_Session._1_TryCatchBlock;
public class _4_TryCatch {
public static void main(String[] args) {
_4_TryCatch tc = new _4_TryCatch();
tc.division(9, 0);
}
public void division(int a, int b)
{
// One try with multiple catch blocks
try
{
int c = a/b;
System.out.println("The division of input " + a + " and" + b + " is -> " + c);
}
catch (ArithmeticException e)
{
e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
System.out.println("An Exception occured inside division method"); // User defined message for more clarification
}
catch (NullPointerException e) {
e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
System.out.println("An Exception occured other than NullPointerException inside division method"); // User defined message for more clarification
}
catch (Exception e)
{
e.printStackTrace(); // This will print the proper hierarchy from where the exception is coming
System.out.println("An Exception occured other than ArithmeticException inside division method"); // User defined message for more clarification
}
}
}package _10_Session._2_ThrowsKeyword;
public class _1_ThrowsKeywordExample {
public static void main(String[] args) {
_1_ThrowsKeywordExample objRef = new _1_ThrowsKeywordExample();
objRef.launchBrowser();
}
public void launchBrowser()
{
System.out.println("launchBrowser ..... ");
launchURL();
}
public void launchURL()
{
System.out.println("launchURL ..... ");
login();
}
public void login()
{
System.out.println("Do login to the application ......-> ");
int a = 9/0;
}
// Below is the stack track of the excetion starting from main method -> launchBrowser -> launchURL -> login
//Exception in thread "main" java.lang.ArithmeticException: / by zero
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.login(_1_ThrowsKeywordExample.java:27)
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.launchURL(_1_ThrowsKeywordExample.java:21)
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.launchBrowser(_1_ThrowsKeywordExample.java:15)
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.main(_1_ThrowsKeywordExample.java:8)
//launchBrowser .....
//launchURL .....
//Do login to the application ......->
//-------------------------------------------------------------------------------------------------------------
//now throws these type of exceptions
// public static void main(String[] args) throws Exception {
//
// _1_ThrowsKeywordExample objRef = new _1_ThrowsKeywordExample();
// objRef.launchBrowser();
//
// }
//
// public void launchBrowser() throws Exception
// {
// System.out.println("launchBrowser ..... ");
// launchURL();
// }
//
// public void launchURL() throws Exception
// {
// System.out.println("launchURL ..... ");
// login();
// }
//
// public void login() throws Exception
// {
// System.out.println("Do login to the application ......-> ");
// int a = 9/0;
// }
// Here all methods are throwing the exceptions so jvm will catch this exception and gives output
//Exception in thread "main" java.lang.ArithmeticException: / by zero
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.login(_1_ThrowsKeywordExample.java:66)
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.launchURL(_1_ThrowsKeywordExample.java:60)
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.launchBrowser(_1_ThrowsKeywordExample.java:54)
//at _10_Session._2_ThrowsKeyword._1_ThrowsKeywordExample.main(_1_ThrowsKeywordExample.java:47)
//launchBrowser .....
//launchURL .....
//Do login to the application ......->
// But this is not right way of handling exceptions
}package _10_Session._2_ThrowsKeyword;
public class _2_ThrowsKeywordExample {
public static void main(String[] args) throws Exception {
_2_ThrowsKeywordExample objRef = new _2_ThrowsKeywordExample();
objRef.launchBrowser();
}
public void launchBrowser() throws Exception
{
System.out.println("launchBrowser ..... ");
launchURL();
}
public void launchURL() throws Exception
{
System.out.println("launchURL ..... ");
login();
}
public void login() throws Exception
{
System.out.println("Do login to the application ......-> ");
try
{
int a = 9/0;
}
catch (Exception e)
{
e.printStackTrace();
System.out.println("Something went wrong while log in to the application");
}
System.out.println("ABC");
}
}package _10_Session._3_ThrowKeyword;
import com.sun.org.apache.bcel.internal.generic.IF_ACMPEQ;
public class _1_ThrowKeywordExample {
// throw keyword is used to create custom exception by user
// as java has not included all kind of exceptions
// and there will be some cases where user needs to create it own exception according to
// some specific conditions
public static void main(String[] args) {
// try {
// throw new Exception("User Defined Exception");
// } catch (Exception e) {
// e.printStackTrace();
// System.out.println("An User defined exception thrown due to the reason .......");
// }
//----------------------------------------------------------------------------------------------
// Use case
// // 1. While reading data from any excel sheet the cell value gets empty or null
// String username = "[email protected]";
// if(username.equals(" ") || username.equals(null))
// {
// try
// {
// throw new Exception("Blank Cell Value Exception");
// }
// catch (Exception e)
// {
// e.printStackTrace();
// System.out.println("The value fetched from the excel sheet cell is either blank or null");
// }
// }
// else {
// System.out.println("Login with -> " + username);
// }
//----------------------------------------------------------------------------------------------
launchURL(" ");
}
//----------------------------------------------------------------------------------------------
// 2. Incorect URL Exception
public static void launchURL(String url)
{
if(url.equals(" "))
{
try
{
throw new Exception("incorrectUrlException");
}
catch (Exception e)
{
e.printStackTrace();
System.out.println("The entered url value is incorrect...");
}
}
}
}Click here-Final Keyword
package _11_Session._1_FinalKeyword;
public class _1_FinalKeyword_1 {
public static void main(String[] args) {
int a = 10;
a = 20;
System.out.println(a);
// By declering a variable final its value cannot be overridden
// final int b = 10;
// b = 20;
// System.out.println(b);
}
}package _11_Session._1_FinalKeyword;
class Parent {
public void test()
{
System.out.println("Hi this is test method in Parent Class");
}
// final public void test()
// {
// System.out.println("Hi this is test method in Parent Class");
// }
}
public class _1_FinalKeyword_2 extends Parent {
@Override
public void test()
{
System.out.println("Hi this is test method in Child Class");
}
public static void main(String[] args) {
_1_FinalKeyword_2 ch = new _1_FinalKeyword_2();
ch.test();
}
}package _11_Session._1_FinalKeyword;
class Parent_1 {
public void test()
{
System.out.println("Hi this is test method in Parent Class");
}
}
//final class Parent_1 {
//
// public void test()
// {
// System.out.println("Hi this is test method in Parent Class");
// }
//
//}
public class _1_FinalKeyword_3 extends Parent_1 {
@Override
public void test()
{
System.out.println("Hi this is test method in Child Class");
}
public static void main(String[] args) {
_1_FinalKeyword_3 ch = new _1_FinalKeyword_3();
ch.test();
}
}Click here-Finally Keyword
package _11_Session._2_FinallyKeyword;
public class _1_FinallyBlock {
public static void main(String[] args) {
int a = 10;
try
{
System.out.println("Division process .....");
int k = a/5;
}
catch (Exception e)
{
System.out.println("Some exception occured .......");
}
// -----------------------------------------------------------------------
// try
// {
// System.out.println("Division process .....");
// //int k = a/5;
// int k = a/0;
// }
// catch (Exception e)
// {
// e.printStackTrace();
// System.out.println("Some exception occured .......");
// }
// // optional block
// finally // This block executes every time whether the exception caught by catch block or not
// {
// System.out.println("Process ended ........");
// }
// -----------------------------------------------------------------------
// try
// {
// System.out.println("Division process .....");
// //int k = a/5;
// int k = a/0;
// }
// catch (NullPointerException e)
// {
// e.printStackTrace();
// System.out.println("Some exception occured .......");
// }
// // optional block
// finally // This block executes every time whether the exception caught by catch block or not
// {
// System.out.println("Process ended ........");
// }
// -----------------------------------------------------------------------
// try
// {
// System.out.println("Division process .....");
// //int k = a/5;
// int k = a/0;
// }
// // optional block & without catch block it also can be used but try & catch should be together
// finally // This block executes every time whether the exception caught by catch block or not
// {
// System.out.println("Process ended ........");
// }
}
}package _11_Session._2_FinallyKeyword;
import java.io.ObjectInputStream.GetField;
public class _2_FinallyBlock {
public static void main(String[] args)
{
int p = getNumber();
System.out.println(p);
}
public static int getNumber()
{
int a = 10;
int b = 20;
try
{
int c = a + b;
return c;
}
catch (Exception e)
{
return -1;
}
finally
{
System.out.println("Bye .... ");
}
}
// ------------------------------------------------------------------------
// public static int getNumber()
// {
// int a = 10;
// int b = 20;
//
// try
// {
// int c = a + b;
// return c;
// }
// catch (Exception e)
// {
// return -1;
// }
// finally
// {
// System.out.println("Bye .... ");
// return 100; // by this return keyword the actual return number is overridden so dont use return in finally
// // other wise it will change the actual return of the method
// }
//
// }
// ------------------------------------------------------------------------
// public static int getNumber()
// {
// int a = 10;
// int b = 0;
//
// try
// {
// int c = a / b;
// return c;
// }
// catch (Exception e)
// {
// e.printStackTrace();
// return -1;
// }
// finally
// {
// System.out.println("Bye .... ");
// return 100; // by this return keyword the actual return number is overridden so dont use return in finally
// // other wise it will change the actual return of the method
// }
//
// }
// ------------------------------------------------------------------------
// public static int getNumber()
// {
// int a = 10;
// int b = 0;
//
// try
// {
// int c = a / b;
// return c;
// }
// catch (NullPointerException e)
// {
// return -1;
// }
// finally
// {
// System.out.println("Bye .... ");
// //return 100; // by this return keyword the actual return number is overridden so dont use return in finally
// // other wise it will change the actual return of the method
// }
//
// }
// ------------------------------------------------------------------------
// public static int getNumber()
// {
// int a = 10;
// int b = 0;
//
// try
// {
// int c = a / b;
// return c;
// }
// catch (NullPointerException e)
// {
// return -1;
// }
// finally
// {
// System.out.println("Bye .... ");
// return 100; // by this return keyword the actual return number is overridden so dont use return in finally
// // other wise it will change the actual return of the method
// }
}
Click here-Access Modifier
package _11_Session._3_AccessModifier.Test;
import javax.sound.sampled.ReverbType;
import _11_Session._3_AccessModifier._1_Company;
public class _3_TestCompany_2 extends _1_Company {
// for protected
public String changeCeoName()
{
ceoName = "Mr. Tom";
return ceoName;
}
// for default
// public void changeCompanyBranch()
// {
// companyBranchName = "Unicorn Systems NYC";
// }
// for private
// public void changeRevenueOfCompany()
// {
// revenue = 10_000;
// }
// for public
public int chnageEmployeeCountOfCompany()
{
employeeCount = 250;
return employeeCount;
}
public static void main(String[] args) {
_3_TestCompany_2 comp = new _3_TestCompany_2();
System.out.println("The changed ceo name of the company is -> " + comp.changeCeoName());
System.out.println("The changed employee count of the company is -> " + comp.chnageEmployeeCountOfCompany());
}
}package _11_Session._3_AccessModifier.Test;
import _11_Session._3_AccessModifier._1_Company;
public class _3_TestCompany_3 {
public static void main(String[] args) {
_1_Company comp = new _1_Company();
// System.out.println("Compnay Revenue is -> " + comp.revenue);
// System.out.println("Compnay CEO name is -> " + comp.ceoName);
// System.out.println("Compnay branch name is -> " + comp.companyBranchName);
System.out.println("Compnay employee count is -> " + comp.employeeCount);
}
}package _11_Session._3_AccessModifier;
public class _1_Company {
private int revenue = 50_000;
protected String ceoName = "Mr. Thomas";
String companyBranchName = "Unicorn Systems Berlin"; // this is default variable without keyword
public int employeeCount = 300;
public static void main(String[] args) {
_1_Company comp = new _1_Company();
System.out.println("Compnay Revenue is -> " + comp.revenue);
System.out.println("Compnay CEO name is -> " + comp.ceoName);
System.out.println("Compnay branch name is -> " + comp.companyBranchName);
System.out.println("Compnay employee count is -> " + comp.employeeCount);
}
}package _11_Session._3_AccessModifier;
public class _2_TestCompany_1 {
public static void main(String[] args) {
_1_Company comp = new _1_Company();
//System.out.println("Compnay Revenue is -> " + comp.revenue);
System.out.println("Compnay CEO name is -> " + comp.ceoName);
System.out.println("Compnay branch name is -> " + comp.companyBranchName);
System.out.println("Compnay employee count is -> " + comp.employeeCount);
}
}