匿名内部类在访问其原语等时是否始终捕获对“this”（外部）对象的引用？

Question

If I have

[EDIT: added the type definition for "Inner"]

interface Inner{
    public void execute();
}

class Outer{
    int outerInt;
    public void hello(){
        Inner inner = new Inner(){
            public void execute(){
                outerInt=5;
            }
        }

        //later
        inner.execute();
    }
}

will the call to inner.execute() set the outerInt variable of that particular Outer object to 5 , wherever it is called from, and for as long as that Inner object exists? Or will it just change a copy of the outerInt variable and not affect the original Outer object?

Answer 1

This will capture and modify the outer this .

See the spec

Answer 2

To answer your newly clarified question (from the comment to my other answer):

Yes .
All inner and local classes will have a reference to their parent's this , even if they never use it.
Demo .

Answer 3

This is not necessarily true. You didn't show is the class declaration for Inner. If Inner has a field called outerInt, then that one will be modified. Otherwise Outer's outerInt will. If you run:

public class Outer {

    int outerInt = 0;

    public void hello() {
        Inner inner = new Inner() {
            @Override
            public void execute() {
                outerInt = 5;
            }
        };

        // later
        inner.execute();
        System.out.println(outerInt);
    }

    public static void main(String[] args) {
        Outer o = new Outer();
        o.hello();
    }
}

class Inner {
    int outerInt;

    public void execute() {

    }
}

You will get 0, not 5.

But by commenting out outerInt in Inner, then you get 5

Answer 4

Yes it does. But if you have a need to use outer class's instance, eg passing to some method, you have to say Outer.this.