good practice with try-finally in java?

Question

I ran into a little problem today where I have a piece of code like this, which made me a little uncomfortable...

   try{
       //stuff...
   } finally {
       //finally stuff
   }

I wonder if such implementation is a good practice in terms of when an exception occurs in the try and is re-thrown to the caller who handles it. Is this equivalent to the code below?

    try{
        //code....
    } catch (Exception e) {
        //handling...
    } finally {
        //finishing up
    }

Duplicate of [Difference between try-finally and try-catch](http://stackoverflow.com/questions/2854910/difference-between-try-finally-and-try-catch) — NullPointerException, May 15 '13 at 18:23
I looked at that one http://stackoverflow.com/questions/2854910/difference-between-try-finally-and-try-catch but I still kind of confused... maybe — lrl, May 15 '13 at 18:30

qqilihq · Accepted Answer · 2013-05-15T18:34:09.660

It's not equivalent, because of the reason you already gave: The exception is still thrown in the first case. And there might be reasons, where you exactly want such a behavior: Close resources, e.g. Streams in finally block, but throw the exception out of the enclosing method, to handle it else where.

Btw., you can also "abuse" try-finally constructs, in case no exception is expected at all:

private StringBuilder buffer = new StringBuilder();

private String getBuffer() {
    try {
            // return current String content of the buffer
            return buffer.toString();
    } finally {
            // assign a new StringBuilder, before method returns
            buffer = new StringBuilder();
    }
}

thanks, in my case it is an 'abuse' as you described it. Nice example by the way... — lrl, May 15 '13 at 20:10

score 2 · Answer 2 · answered May 15 '13 at 18:30

Not exactly, a try/finally block without catch is the equivalent of

try {
    // ...
} catch (Exception e) {
    throw;
} finally {
    // finishing up
}

Where you just re throw the exception without handling it. Omitting the catch block is good if this is what you intended to do, it improves the code readability.

good practice with try-finally in java?

2 Answers2