Sometimes, there will be no data in the Code | Hot methods tab, even if the method sampling was enabled. The most common reason is that the application did not generate enough load to provide the method sampler with data. The method sampler only samples threads that are actively running Java code. If the recording is short and the threads are spending most of their time waiting and doing nothing, chances are that no samples will be recorded at all. If you aren't profiling a production system, try to stress your application during profiling, if possible in a manner that is close to the real deployment scenario.

When using native method sampling, all samples will be stored. Normally, only the samples for threads executing Java will be stored. Don't be surprised if you find almost all of the native samples to be in some native method, such as ntdll.dll#KiFastSystemCallRet, even when the system is mostly idle.