Here you can find the source of isJavaImmutable(Class cls)
public static boolean isJavaImmutable(Class cls)
//package com.java2s; // Licensed under the Academic Free License version 3.0 import java.util.*; public class Main { private static HashMap javaImmutables = new HashMap(); /**/*from ww w .j av a 2 s . c om*/ * Return if the specified Java class represents an immutable type. */ public static boolean isJavaImmutable(Class cls) { return javaImmutables.get(cls.getName()) != null; } }