100% CPU Utlization by Java Application

Question

I am trying to analyze the java application using VisualVM tool and am getting the following statistics. VisualVM screenshot .

What I don't understand is why my app is utilizing approx 100% of CPU, and what are the ways I can detect and resolve memory-related issues in java application.

The project is developed on Spring Boot and is deployed on Apache Tomcat Server.

Thanks.

Edit: My project used to utilize a max of 30% of CPU but now it's utilizing 100% and because of it most of the APIs are taking a lot of time to respond.

VisualVM can profile your application and tell you where time is spent. — Thorbjørn Ravn Andersen, Nov 19 '20 at 13:41
This does not look like a memory issue. Either you use inefficient algorithms or your program simply has a lot to do. — Henry, Nov 19 '20 at 13:44
Looking at that screenshot, you are generating a lot of garbage, which means a lot of garbage collection and that can lead to excessive CPU usage. — M. Deinum, Nov 19 '20 at 13:44
@M.Deinum Then gc cpu usage should be higher. Time probably goes somewhere else. — Thorbjørn Ravn Andersen, Nov 19 '20 at 13:53
@M.Deinum can you please illustrated how do you know that my application is generating a lot of garbage. — Kirat Kumar, Nov 19 '20 at 13:56
@ThorbjørnRavnAndersen I just started using VisualVM and trying to profile my application but it's not working. — Kirat Kumar, Nov 19 '20 at 14:00
That is what you see in your screenshot. Those blue spikes is consumed memory, when it gets to high it will start to GC. Ifyou look close you might see that those spikes on CPU and memory correlate. — M. Deinum, Nov 19 '20 at 14:02
@ThorbjørnRavnAndersen sorry for the vague comment I started profiling but it is not showing any results. — Kirat Kumar, Nov 19 '20 at 14:21
@KiratKumar You might want to experiment with VisualVM on a simpler application running on your local machine to know it a little bit better and then try agin. — Thorbjørn Ravn Andersen, Nov 19 '20 at 14:48

score 2 · Accepted Answer · answered Nov 19 '20 at 14:03

2

You could use a Profiling tool like JProfiler or VisualVM to analyze what your application is doing at that time. You could also connect a debugger and just "pause" the threads, that's a hack that may give you some hint on where to look for what is actually happening.

From your screenshot I'm not really seeing any memory specific issues, but using a profiling tool will also allow you to analyze which classes have instances with allocated memory.

answered Nov 19 '20 at 14:03

Andreas Hartmann

1,825
4
23
36

You noticed that the screen dump is from VisualVM? – Thorbjørn Ravn Andersen Nov 19 '20 at 14:14
I am accepting this answer because I used VisualVM for profiling and it helped me to identify the problem. One of my API has a while loop which in certain conditions didn't exit and that while loop was using a lot of GPU. I simplely removed that code and now project is working properly. – Kirat Kumar Nov 21 '20 at 08:40

100% CPU Utlization by Java Application

1 Answers1