如何删除传递给Java方法的对象? [英] How can I delete an object passed into a Java method?

问题描述

我知道Java通过引用传递对象，因此当将对象作为参数传递给方法时，对方法内部参数进行本地处理的所有操作都将对实际对象进行.

I know that Java passes objects by reference, so when an object is passed as an argument into a method, anything that is done locally to the argument inside the method is done to the actual object.

void main(){
 String[] array1 = {"a","b","c"};
 someMethod(array1);
 print(array1.length);
}

void someMethod(String[] array){
 /..code here../
 array = null;
}

当我尝试打印array1.length时，我希望得到一个空指针异常，因为我的方法将其设置为null.但是，这没有发生.有这个原因吗?

I would expect to get a null pointer exception when trying to print array1.length because my method set it to null. However this is not happening. Is there a reason for this?

推荐答案

array只是该对象的另一个指针.因此，当您设置array = null;时，只是将指针设置为null.该对象仍然存在于堆中，并且仍由main()中的array1指向.

array within someMethod is just another pointer to the object. So when you're setting array = null;, you're just setting the pointer to null. The object still exists on the heap, and is still pointed to by array1 in main().

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