Tomcat freezes server

[Dimka]

Hello

I have recently upgraded to 7.5.2 and I have a few clients that use Tomcat , they were complaining that tomcat don't decompile their .war files so I went to have a look ,and I have found that after I make tomcat restart the whole system freezes .

Don't know what could be the possible reason

desperatly need help!
all advices are welcome

Thanks in advance