package test;    class TestGC {   private String str = "hello";      TestGC(String str) {     this.str = str;   }      public void finalize() {     System.out.println(str);   } }    public class Hello {   /**    * @param args    */  public static void main(String[] args) {     // TODO 自動生成方法存根     System.out.println("hello");        TestGC test = new TestGC("test1");     test = new TestGC("test2");     test = null;//注釋掉這一句，test1被回收。加上則先回收test2,后test1     System.gc();   } }