Re: Alternative to System.runFinalizersOnExit()?

From:

Thomas Hawtin <usenet@tackline.plus.com>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 14 Nov 2006 19:45:35 +0000

Message-ID:

<455a1ca7$0$8719$ed2619ec@ptn-nntp-reader02.plus.net>

Red Orchid wrote:

Thomas Hawtin <usenet@tackline.plus.com> wrote or quoted in
Message-ID: <455a02fc$0$8733$ed2619ec@ptn-nntp-reader02.plus.net>:

     // STILL WRONG (and daft):
     OutputStream out = null
     try {
         out = new BufferedOutputStream(
             new FileOutputStream(file)
         );
         ...
         out.flush();
     } finally {
         if (out == null) {
             out.close();
         }
     }

What if construction of the BufferedInputStream failed due to lack of
memory, or some other reason? Leak.

( I assume that the above "if (out == null)" is mis-typed out.)

Yes, that is a mistake!

Why still wrong ?

Though an exception is thrown because of some reason,
'finally' block will be executed.

For the worst.
Even if the lack of memory happens, 'file' resource will be released.

'file' is not a resource. new FileOutputStream(file) is. If the
BufferedOutputStream throws an OOME, then it will leak. There is no
local variable referring to the resource.

As a point of extreme obscurity, if the *allocation* of the
BufferedOutputStream object itself fails, then the FileOutputStream will
not be created. If the byte[] buffer allocation fails, then it will leak
resources.

Tom Hawtin