CODEWITHSUNDEEP
java
deinocheirus
deinocheirus

Reputation: 1863

Am I letting the 'this' reference escape? (inner class in constructor instantiation, no event listener, no threads)

I am instantiating an inner class in my constructor but I'm not using it to start threads or as an event listener. For example:

public class Something {

    final InnerSomething innerSomething = new InnerSomething();

    public Something(Param arg) {
        super(arg);
    }

    private class InnerSomething {...}

    ...
}

EDIT: I copied & pasted the code from somewhere else and forgot to delete the "abstract" keyword.

EDIT2: "My" definition of "'this' reference escape" is the one found in the book Java Concurrency in Practice.

With the above code, am I allowing the 'this' reference to "escape"?

Upvotes: 4

Views: 327

Answers (2)

assylias
assylias

Reputation: 328737

Technically you are since InnerSomething will have a reference to this before Something's constructor returns.

However if you don't publish the reference and don't do anything with it in InnerSomething's constructor, it should not create problems. Note that it would be better to mark innerSomething private as one could access this through the package-private field.

If you refer to JCiP #3.2.1, they state:

More specifically, the this reference should not escape from the thread until after the constructor returns. The this reference can be stored somewhere by the constructor so long as it is not used by another thread until after construction.

Upvotes: 8

duffymo
duffymo

Reputation: 308928

I don't believe so. "Escape" means public access to a private reference that's mutable. I don't see that in the code you've posted.

Do we agree on the meaning of the term?

Upvotes: 1

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