What is JVM Logs

The WAS application server redirects content System.out stream to SystemOut.log and System.err stream to SystemErr.log. The SystemOut.log and SystemErr.log are also known as JVM logs. The WebSphere Application Server writes to this log and you can write into this log from your application by using println(), printStackTrace() calls

These logs are created for every WebSphere Application Server process, such as deployment manager, node agent, nodes,.. You can find these logs in profiles/<profilename>/logs/<processname> folder.