The answer on this question is not easy. It depends on the business application and the requirements. There are few thing that you should know and that help for the first moments. Just in case that you have over thousand(s) of classes that should be loaded (and that is a common value) increase the -X:MaxPermSize to a value that is suitable for your application. The default value is 64MB and is optimal for small applications.

The Java Garabe Collector (GC) is running every time when some of the objects are not more used and have no references to other objects in use. If you have a problem with the performance of your application, please update the value for the heap size. The best is to set the starting heap size and maximum heap size to the same value, so i suggest to use -Xms1024m -Xmx1024m. The first option is for the starting heap size value and the second is for the max heap size value.

If you use a linux desktop environment and constantly use bash in a terminal, you repeat some command every day . To have access to the last 10.000 (yes, ten thousand commands) i have extened the HISTORY variable in my .bashrc.

I have added this to .bashrc:


# HISTORY FILE
export HISTIGNORE="&:[ ]*:exit"
export HISTSIZE=10000
export HISTCONTROL=erasedups


After a while, here is the list of top 10 most used commands in bash:

$ history|awk '{print $2}'|awk 'BEGIN {FS="|"} {print $1}'|sort|uniq -c|sort -rn|head -10

1512 cd
1335 hg
869 ls
470 sudo
408 rm
391 ssh
353 less
274 mv
231 find
225 ant