Here you can find the source of getWrapperClass(Class> primitiveClass)
public static Class<?> getWrapperClass(Class<?> primitiveClass)
//package com.java2s; import java.util.Map; public class Main { static private Map<Class<?>, Class<?>> primitiveClasses; public static Class<?> getWrapperClass(Class<?> primitiveClass) { return primitiveClasses.get(primitiveClass); }/* ww w. j a va 2s. c om*/ }