[Helma-user] Helma OutOfMemory

[Michael Platzer]

Hi list,

 From time to time a helma developer might find herself in the situation 
[1], where an application runs out of memory (and therefore crashes) and 
she has no clue what causes that memory leak. Hannes recently gave me 
the decisive hint to look for 'memory profilers for Java' [2] (in 
particular: YourKit [3]), if one happens to be in such a situation.

By adding '-XX:+HeapDumpOnOutOfMemoryError' to the Java start options, 
the JVM will save the complete memory content on to the disk the next 
time that an OutOfMemory-error occurs. A tool like YourKit now allows 
you to open the dumped file, and lets you sort all loaded classes by 
their size. That way you should be able to quickly identify the classes, 
resp. the code that led to the memory leak. At least in our case, it was 
that easy.

Just thought this information might be worth sharing,
  michi


[1] http://www.google.at/search?q=+site:helma.org+helma+outofmemory
[2] http://www.google.at/search?q=memory+java+profiling
[3] http://www.yourkit.com/