Question

I was wondering, is it good practice to return from try block?

package debug;

/**
 *
 * @author Owner
 */
public class Main {

  public static void main(String[] args) {
    System.out.println(fun());
  }

  static boolean cleanup() {
    // Fail to cleanup.
    return false;
  }

  static boolean fun() {
    boolean everything_is_fine = true;
    try {
      System.out.println("open file stream");
      return everything_is_fine;
    } finally {
      everything_is_fine = cleanup();
    }
  }
}

---

I first thought false will be printed. However, here is the output :

open file stream
true

As you can see, if I am having return statement within try block, I will miss the fail status during finally cleanup.

Shall I have the code as :

  static boolean fun() {
    boolean everything_is_fine = true;
    try {
      System.out.println("open file stream");      
    } finally {
      everything_is_fine = cleanup();
    }
    return everything_is_fine;
  }

As long as the returned value from finally block is concerned, shall I avoid return from try?

Answer 1

Your suggested code (at the end of the question) is fine. You can return from the finally block, but you should not – for example eclipse shows a warning “finally block does not complete normally”.

In fact, the try/finally aren’t directly related to the return. It seems so here, because it is the only construct in the method, but you can have other code after that (for example – event notifications), and then return.

As for your question – you can’t change the value of the returned variable in the finally block if it is already returned. So don’t return from try.