CPU hogging apps

Hi All!
 
We have several applications on WO 4.5.1 (update 4) running on Solaris  2.8.
And the problem is that several times a day they go "bad" - taking more  that 
60% of CPU and staying in this state, never come out of it. So we have to  
kill the instance and start another one. This happens to several different  
application, so I kinda suspect it's not the code itself.
 
I know about Java Heap Size options and we have them set quite high. Does  
not seem to make any difference. And there are no OutOfMemory exceptions in log  
files. In fact, there are no exceptions.
 
Problem seems to have gotten worse since we moved to a new hardware. It has  
the same configuration, only it's a newer machines. If on old hardware it  
happened one or two times a week, now it's happening several times a day, which  
is becoming a problem for admin guys. 
 
I searched archives, but pretty much all advises are to increase Java Heap  
Size. 
Is there anything else we can do? Upgrade to 5.0 is not an option at  the 
moment.
 
Thank you very much in advance,
 
Marina Mechtcheriakova
Developer
 
America Online