Very common error in Oracle Apps, either with the internal or external site.Examined the Apache,OPMN debug files but there are no specific errors.
As per Oracle, this error could be one of the PORT belongs to the jvm cache.
If the JVM is not available, Distributed Caching is unable to copy the class across to
other jvm's and you get the error "500 Internal Server Error java.lang.NoClassDefFoundError"
Solution:
1) Check the JVM Caching Port ("s_java_object_cache_port") in Context fine defined is used by any other application by stopping all the opmn services.
If the Port is used by other applciation, change the port in the Context file and run the adautocfg.sh and start all the services.
2) Temporarily we can also disable the Distributed JVM Cache by changing the line in $ORA_CONFIG_HOME/10.1.3/j2ee/oacore/config/oc4j.properties that says
LONG_RUNNING_JVM=true to LONG_RUNNING_JVM=false.
Disabling Distributed JVM Cache is achieved by changing "LONG_RUNNING_JVM=" from "true" to "false" in the oc4j.properties. This is controlled by AutoConfig parameter "s_long_running_jvm".
