For Sun JDKs, the Data Collector configuration enables verbose garbage collection output using the -Xloggc generic JVM argument. By default, the -Xloggc causes the JVM to generate class loading and unloading events to the native standard output stream. The process might fill the log files and consume excessive disk space.
To suppress class loading and unloading events, use your application server to add the -XX:-TraceClassUnloading -XX:-TraceClassLoading options to the arguments for the Java™ Virtual Machine. Then, Restart the instance of the application server that is being monitored by the Data Collector.