Exception in thread "main" java.lang.OutOfMemoryError, How to find and fix? [duplicate]

Question

I'm trying to programming a crossword creator. using a given dictionary txt file and a given pattern txt file. The basic idea is using DFS algorithm. the problem begin when the dictionary file is v-e-r-y big (about 50000 words). then i recive the :

Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded

i know that there is a part in my program that wastes memory, but i don't know where it is, how to find it and how to fix it

Answer 1

Does it really waste memory ? If you're loading a sizeable dictionary, then you may simply want to increase the JVM memory settings (the JVM has a maximum memory allocation - dependent on your platform, and configurable).

e.g.

$ java -Xmx512m ....

would increase the maximum memory allocation of the JVM to 512m.

If you think you have a memory leak (garbage collection not kicking in due to references not being released) then a profiler such as YourKit may be of use. Note that this isn't free, but the trial version may help you solve your problem.

Answer 2

To solve this problem ( in linux based os ) do following

1) increase memory (so that this problem don't come frequently ) by configuring "domain.xml" in

/glassfish/domain/domain1/config

search for

<jvm-options>-XX:MaxPermSize=

set it to higher value eg- 198m or 256m

2) kill the glassfish process to free the port on which it was running ( in my case it was 8686) open terminal (in linux based os) and type -

sudo netstat -npl | grep 8686

this will result in something like..

tcp6 0 0 :::8686 :::* LISTEN 3452/java

next use

kill -9 3452 to kill that process ( 3452 in this case )

Now try to start glassfish, it should start.