Java - If I return in a catch block, will the finally block be executed? [duplicate]

StackOverflow https://stackoverflow.com/questions/17980172

  •  04-06-2022
  •  | 
  •  

Question

This is what I'm trying to do:

try {

    //code
} catch (Exception e) {

    return false;
} finally {

    //close resources
}

Will this work? Is it bad practice? Would it be better doing this:

boolean inserted = true;

try {

    //code
} catch (Exception e) {

    inserted = false;
} finally {

    //close resources
}

return inserted;
Was it helpful?

Solution

Yes, it will. The only things that can prevent a finally block to execute (AFAIR) are System.exit(), and an infinite loop (and a JVM crash, of course).

OTHER TIPS

The finally block is executed always, unconditionally, as the last thing the try-catch-finally block does. Even if you execute Thread#stop against it, the finally block will still execute, just as if a regular exception ocurred.

Not just that, if you return from finally, that return value will trample over the return from either try or catch.

BTW Your first example is not just fine, but preferred. In the second example the reader must chase around the assignments to the variable, which is a tedious job and lets bugs slip through very easily.

Both are approximately the same. However, be careful with the following case:

int i = 0;

try
{
    //code
}
catch(Exception e)
{
    return i;
}
finally
{
    i = 1;
}

0 is what will be returned.

I just wanted to add that it's described in the specs:

If the catch block completes abruptly for reason R, then the finally block is executed.

where of course

It can be seen, then, that a return statement always completes abruptly.

Licensed under: CC-BY-SA with attribution
Not affiliated with StackOverflow
scroll top