Trouble Shooting Connection Problems


When a profiling session cannot be established, the first thing to do is to have a look at the terminal output of the profiled application or application server. For application servers, the stderr stream is often written to a log file. This may be a separate log file and not the main log file of the application server. For example, the Websphere application server writes a native_stderr.log file where only the stderr output is included. Depending on the content of the stderr output, the search for the problem takes different directions:

Connection problems

If stderr contains "Waiting for connection ...", the configuration of the profiled application is ok. The problem might then be related to the following questions:

Port binding problems

If stderr contains an error message about not being able to bind a socket, the port is already in use. In that case, check the following questions:

If there are no lines in stderr that are prefixed with JProfiler> and your application or application server starts up normally, the -agentpath:[path to jprofilerti library] VM parameter has not been included in the Java call. You should find out which java call in your startup script is actually executed and add the VM parameters there.