Java 1.6 Compilation fix

Author: venkat-cheenu

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

@@ -10,7 +10,7 @@ public class JSONParserConfiguration extends ParserConfiguration {
     /**
      * Thread-safe holder for the system-wide default configuration.
      */
-    private static final AtomicReference<JSONParserConfiguration> GLOBAL_CONFIG = new AtomicReference<>(null);
+    private static final AtomicReference<JSONParserConfiguration> GLOBAL_CONFIG = new AtomicReference<JSONParserConfiguration>(null);
 
     /**
      * Sets the system-wide global JSONParserConfiguration.