Re: How to get the current allocated total size of an ArrayList?
On 2/23/2011 7:43 AM, Robin Wenger wrote:
Assume I setup an ArrayList like:
ArrayList<String> mylines = new ArrayList<String>();
and add lots of lines/strings to it:
while(...)
mylines.add(...);
How can I find out the total size (in Bytes) which is currently allocated by the ArrayList?
Occasionally I get an OutOfMemory exception. Can I prevent this by preallocating everything in one step
in advance instead of doing this little by little with every add()?
Robin
You can prevent this by:
1) Make sure you're not holding on to objects you no longer need.
Pack-ratting is the term for holding on to objects too long.
2) Look into tuning your GC settings. -Xmx512m might be a good start.
See
<http://download.oracle.com/javase/1.3/docs/tooldocs/solaris/java.html#options>
3) Consider streaming processing rather than loading the entire data
set into memory before processing. This may have additional benefits on
efficiency (depending on the processing being done). The benefit may be
outweighed by code complexity, so use judiciously.
Hope this helps, gl.
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