doubt about try catch finally and method return

[raminaa niilian]

Hi
thank you for reading my post
I am just wondering why should the finally block execute even if i return from the method in try block ?

 public static void main(String[] args) {
        
        try{
            System.out.println("It is try");
            return;
        }catch(Exception ex){
            System.out.println("It is catch");
        }finally{
            
            System.out.println("It is finally");
        }
        
        
        // TODO code application logic here
    }

about the above code it always execute the finally block , i was thinking that return will return from he method where ever it is :-)

[Keith Lynn]

If the finally block terminates abruptly like with a return statement, then if there was a return statement executed in the try block or in one of the catch blocks, that statement is ignored, and the try-catch-finally ends for the reason the finally ended.

[Sanjaya Sugiarto]

finally is ALWAYS terminated, no matter where you place your return in try/catch block or even if exceptions occur.

[Garrett Rowe]

Well... not exactly always

public class ExitAbruptly
{
   public static void main(String[] args)
   {
      try
      {
         System.out.println("in try block");
         System.exit(0);
      }
 
      finally
      {
         System.out.println("what about me?");
      }
   }
}

[Sanjaya Sugiarto]

Originally posted by Garrett Rowe:
Well... not exactly always

public class ExitAbruptly
{
   public static void main(String[] args)
   {
      try
      {
         System.out.println("in try block");
         System.exit(0);
      }
 
      finally
      {
         System.out.println("what about me?");
      }
   }
}

Clever response!!! My bad to say "always", must remember: for every rule there is at least one exception...thanks to point it out

[Henry Wong]

It's actually interesting that the finally clause is guaranteed to run (assuming JVM doesn't exit). Instead of common code that looks like this...

  private int previousSlot = 0;
  public synchronized int getNextSlotToUse(String newdata) {
    int retval = previousSlot;
    previousSlot = processTablesInDB(newdata);
    return retval;
  }

You can do something like this...

  private int previousSlot = 0;
  public synchronized int getNextSlotToUse(String newdata) {
    try {
      return previousSlot;
    } finally {
      previousSlot = processTablesInDB(newdata);
    }
  }

Now... I am not going to say which is better though...
Henry
[ October 21, 2006: Message edited by: Henry Wong ]

[Ilja Preuss]

Originally posted by raminaa niilian:
I am just wondering why should the finally block execute even if i return from the method in try block ?

Well, because that's exactly what it is meant to be used for: executing code that should *always* be executed when the try block ends. Common use is freeing resources that have been in use, such as streams, database connections etc. When you are done with them, you typically want to release them no matter what.