Here you can find the source of isCollectionClass(Class> clazz)
private static boolean isCollectionClass(Class<?> clazz)
//package com.java2s; //License from project: Apache License import java.util.Collection; public class Main { private static boolean isCollectionClass(Class<?> clazz) { return clazz == Collection.class || clazz == java.util.List.class || clazz == java.util.Set.class || clazz == java.util.Map.class || clazz == java.util.SortedSet.class // extension to the specs || clazz == java.util.SortedMap.class; // extension to the specs }/*from w w w . j ava 2s . co m*/ }