Diogo Oliveira de Melo

Finally is executed even if code returns inside try

I came across a piece of code where there was a return statement inside the try and the finally with some code as well. I don’t have much experience with Java and, until today, return meant end of execution for me. Then, convinced that there was something fishy with that piece of code, I decided to put it to the test.

I wrote the following code inside A.java:

public class A {
    public int t() {
        try {
            System.out.println("try");
            return 2;
        } catch (Exception e) {
        } finally {
            System.out.println("finally");
        }
        return 1;
    }

    static public void main(String []args) {
        A a = new A();
        System.out.println("t: " + a.t());
    }
}

Then I compiled and ran it. Here is the result:

dmelo@merov2:~/proj2/java$ java A
try
finally
t: 2

See that it is printing the “finally” line? Today I’ve learned it calls the finally block even if you return from the method inside the try. My next thought was: in what situation doesn’t Java run the finally block? I came across a StackOverflow Question that solved the question. As stated by jodonnell, Java will not run the finally block if one of the following happens:

1. System.exit() is called;
2. another thread interrupts current one (via the interrupt method);
3. JVM crashes first.