Difference between final and effectively final

Question

I\'m playing with lambdas in Java 8 and I came across warning local variables referenced from a lambda expression must be final or effectively final. I know tha

Answer 1

According to the docs:

A variable or parameter whose value is never changed after it is initialized is effectively final.

Basically, if the compiler finds a variable does not appear in assignments outside of its initialization, then the variable is considered effectively final.

For example, consider some class:

public class Foo {

    public void baz(int bar) {
        // While the next line is commented, bar is effectively final
        // and while it is uncommented, the assignment means it is not
        // effectively final.

        // bar = 2;
    }
}