I am running tomcat 5.5 on x86_64 CentOS 5.7 using 32-bit Oracle Java 1.6.0.
JVM process used by tomcat has 6421 pid. Tomcat is working fine.
When run
I was getting the same error running:
watch -n .5 "jstack 26259"
Doing as sudo it works:
sudo watch -n .5 "jstack 26259"