java 变量 final 小结

通过查看hashCode发现，变量声明final后，不能修改，上级修改时候，重新获得对象hashCode变化

public static void main(String[] args) {
// TODO Auto-generated method stub
Document sss=new Document().append("aaa","ssss");

System.out.println("DA==="+sss.toJson()+ "@" + sss.hashCode());
ProcessTextMsg.start(sss);
sss.put("aaa","改变");
System.out.println("DA==="+sss.toJson()+ "@" + sss.hashCode());
}

=======================

public static void start(final Document eventMsg){
 
System.out.println(eventMsg.hashCode());
try {
Thread.sleep(111);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(eventMsg.hashCode());
System.out.println(eventMsg.toJson());

}