JAVA-18701 :- Minor fixes to make the project compile and tests run. (#16684)

Author: amit2103

core-java-modules/core-java-os/pom.xml

@@ -59,6 +59,10 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>17</source>
+                    <target>17</target>
+                </configuration>
             </plugin>
         </plugins>
     </build>

core-java-modules/core-java-os/src/test/java/com/baeldung/java9/process/ProcessUnderstandingUnitTest.java

@@ -19,7 +19,7 @@ class ProcessUnderstandingUnitTest {
     @Test
     public void givenSubProcess_whenEncounteringError_thenErrorStreamNotNull() throws IOException {
         Process process = Runtime.getRuntime()
-            .exec("javac -cp src src\\main\\java\\com\\baeldung\\java9\\process\\ProcessCompilationError.java");
+            .exec("javac -cp src src\\test\\resources\\com\\baeldung\\java9\\process\\ProcessCompilationError.java");
         BufferedReader error = new BufferedReader(new InputStreamReader(process.getErrorStream()));
         String errorString = error.readLine();
         assertNotNull(errorString);

core-java-modules/core-java-os/src/main/java/com/baeldung/java9/process/ProcessCompilationError.java renamed to core-java-modules/core-java-os/src/test/resources/com.baeldung.java9.process/ProcessCompilationError.java

@@ -3,5 +3,5 @@
 public class ProcessCompilationError {
     //This method has been written to generate error to display 
     //how process errorStream() can consume error
-    //public static void();
+    public static void();
 }