fix: null handling (#176)

Author: sattvikc

src/main/java/io/supertokens/storage/postgresql/utils/ConfigMapper.java

@@ -16,11 +16,11 @@
 
 package io.supertokens.storage.postgresql.utils;
 
-import com.fasterxml.jackson.annotation.JsonAlias;
-import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonNull;
 import com.google.gson.JsonObject;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonAlias;
 import io.supertokens.pluginInterface.exceptions.InvalidConfigException;
 
 import java.lang.annotation.Annotation;
@@ -72,21 +72,9 @@ private static <T> Field findField(Class<T> clazz, String key) {
     }
 
     private static <T> void setValue(T object, Field field, JsonElement value) throws InvalidConfigException {
-        boolean foundAnnotation = false;
-        for (Annotation a : field.getAnnotations()) {
-            if (a.toString().contains("JsonProperty")) {
-                foundAnnotation = true;
-                break;
-            }
-        }
-
-        if (!foundAnnotation) {
-            return;
-        }
-
         field.setAccessible(true);
         Object convertedValue = convertJsonElementToTargetType(value, field.getType(), field.getName());
-        if (convertedValue != null) {
+        if (convertedValue != null || isNullable(field.getType())) {
             try {
                 field.set(object, convertedValue);
             } catch (IllegalAccessException e) {
@@ -95,6 +83,10 @@ private static <T> void setValue(T object, Field field, JsonElement value) throw
         }
     }
 
+    private static boolean isNullable(Class<?> type) {
+        return !type.isPrimitive();
+    }
+
     private static Object convertJsonElementToTargetType(JsonElement value, Class<?> targetType, String fieldName)
             throws InvalidConfigException {
         // If the value is JsonNull, return null for any type