以下实例演示了如何使用 removeAll () 方法来计算两个数组的差集：

/*
 author by w3cschool.cc
 文件名：Main.java
 */

import java.util.ArrayList;

public class Main {
   public static void main(String[] args)  {
      ArrayList objArray = new ArrayList();
      ArrayList objArray2 = new ArrayList();
      objArray2.add(0,"common1");
      objArray2.add(1,"common2");
      objArray2.add(2,"notcommon");
      objArray2.add(3,"notcommon1");
      objArray.add(0,"common1");
      objArray.add(1,"common2");
      objArray.add(2,"notcommon2");
      System.out.println("array1 的元素" +objArray);
      System.out.println("array2 的元素" +objArray2);
      objArray.removeAll(objArray2);
      System.out.println("array1 与 array2 数组差集为："+objArray);
   }
}

以上代码运行输出结果为：

array1 的元素[common1, common2, notcommon2]
array2 的元素[common1, common2, notcommon, notcommon1]
array1 与 array2 数组差集为：[notcommon2]