Description Christopher Unkel 2006-07-25 19:30:25 EDT

The compiler incorrectly allows writes to final fields, within the constructor for the class declaring a field, when the access is not of the proper form "f = ", or "this.f =".

For example, in the following code:

public class FinalBug {
    // incorrectly passes compilation
    static class Test5 {
        private final Object o;
        
        Test5() {
            Test5 other = this;
            other.o = new Object(); // illegal!  other.o is not assignable
        } // error: this.o is not definitely assigned
    }
    
    // flags wrong statement as error
    static class Test6 {
        private final Object o;
        static Test6 initing;
        
        Test6() {
            initing = this;
            System.out.println("greetings");
            Test6 other = initing;
            other.o = new Object(); // illegal!  other.o is not assignable
            o = new Object(); // legal
        }
    }
}

There should be an error flagged within class Test5, on the marked line, and none is flagged.  Also field o is not "definitely assigned" (in terms of the language specification's meaning of "definitely assigned") at the end of the constructor of Test5, and that is also an error that should be flagged.

Likewise, in Test6, the assigment to other.o is illegal.  Eclipse incorrectly flags the assigment to o as illegal.