Add tests (+ fix bugs) & missing javadoc

src/main/java/org/json/JSONParserConfiguration.java

@@ -30,22 +30,50 @@ public class JSONParserConfiguration extends ParserConfiguration {
 
     @Override
     protected JSONParserConfiguration clone() {
-        return new JSONParserConfiguration();
+        JSONParserConfiguration clone = new JSONParserConfiguration(overwriteDuplicateKey);
+        clone.maxNestingDepth = maxNestingDepth;
+        return clone;
     }
 
+    /**
+     * Defines the maximum nesting depth that the parser will descend before throwing an exception
+     * when parsing a map into JSONObject or parsing a {@link java.util.Collection} instance into
+     * JSONArray. The default max nesting depth is 512, which means the parser will throw a JsonException
+     * if the maximum depth is reached.
+     *
+     * @param maxNestingDepth the maximum nesting depth allowed to the JSON parser
+     * @return The existing configuration will not be modified. A new configuration is returned.
+     */
     @SuppressWarnings("unchecked")
     @Override
     public JSONParserConfiguration withMaxNestingDepth(final int maxNestingDepth) {
-        return super.withMaxNestingDepth(maxNestingDepth);
+        JSONParserConfiguration clone = this.clone();
+        clone.maxNestingDepth = maxNestingDepth;
+
+        return clone;
     }
 
+    /**
+     * Controls the parser's behavior when meeting duplicate keys.
+     * If set to false, the parser will throw a JSONException when meeting a duplicate key.
+     * Or the duplicate key's value will be overwritten.
+     *
+     * @param overwriteDuplicateKey defines should the parser overwrite duplicate keys.
+     * @return The existing configuration will not be modified. A new configuration is returned.
+     */
     public JSONParserConfiguration withOverwriteDuplicateKey(final boolean overwriteDuplicateKey) {
-        JSONParserConfiguration newConfig = this.clone();
-        newConfig.overwriteDuplicateKey = overwriteDuplicateKey;
+        JSONParserConfiguration clone = this.clone();
+        clone.overwriteDuplicateKey = overwriteDuplicateKey;
 
-        return newConfig;
+        return clone;
     }
 
+    /**
+     * The parser's behavior when meeting duplicate keys, controls whether the parser should
+     * overwrite duplicate keys or not.
+     *
+     * @return The <code>overwriteDuplicateKey</code> configuration value.
+     */
     public boolean isOverwriteDuplicateKey() {
         return this.overwriteDuplicateKey;
     }