Here you can find the source of assertNotNull(Object argumentThatMustNotBeNull, String argumentName)
private static void assertNotNull(Object argumentThatMustNotBeNull, String argumentName)
//package com.java2s; //License from project: Apache License public class Main { private static void assertNotNull(Object argumentThatMustNotBeNull, String argumentName) { if (argumentThatMustNotBeNull == null) { throw new IllegalArgumentException(argumentName + " must not be null."); }/* w ww .ja v a2s .co m*/ } }