[jdom-interest] Bug Report: Memory Leak in SAXHandler.java

[Jason Hunter]

You're not the first to find this.  :-)  Try the CVS code.

-jh-

"Kevin A. Roll" wrote:
> 
> Greetings all... I am hoping that this is the proper place to make a bug
> report, and that the information will get into the proper hands.
> 
> I've uncovered a rather serious memory leak in JDOM b8. This can literally
> cause over 100 megabytes of memory to get sucked up, as I've seen in my own
> application. The problem is on line 721 of the file
> org/jdom/input/SAXHandler.java. The code reads:
> 
> String data = textBuffer.toString();
> textBuffer.setLength( 0 );
> 
> This would appear to simply convert the StringBuffer to a String and assign
> it to a new String. The problem, as I discovered after some intense
> debugging, is in the internal implementation of StringBuffer. It attempts
> to conserve memory by simply sharing the memory with the new String, and
> setting an internal flag called shared. Once this flag is set, any
> alteration to the StringBuffer causes the memory to be duplicated. Since
> this buffer is used as a temporary buffer by the class and constantly
> altered, the effect is that hundreds of 8192-byte blocks are allocated and
> remain stuck in memory.
> 
> When I altered this line to read
> 
> String data = new String( textBuffer.toString() );
> 
> the problem went away. I saw no evidence of extra memory blocks that didn't
> belong.
> 
> I noticed that there is a comment above this section that recommends
> eventually using textBuffer.substring(0) once JDK 1.1 support is removed.
> Someone may already be at least partially aware of this problem, if not
> fully aware of the ramifications.
> 
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