Marcos Medrado Rubinelli wrote:
jps gets its information from the files stored under /tmp/hsperfdata_*, so when a cron job clears your /tmp directory, it also erases these files. You can submit jobs as long as your jobtracker and namenode are responding to requests over TCP, though.
I never knew that.ps -ef | grep java works quite well; jps has fairly steep startup costs and if a JVM is playing up, jps can hang too