Java Debug Confusion [duplicate]

This question already has answers here: 开发者_如何学Go Debug a java application without starting the JVM with debug arguments (5 answers) Closed 7 years ago.

Is a Java program debuggable only when the VM is running in Debug Mode?

Is there any way to change it at runtime?

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No, there's no way to change it at runtime.

If at all possible, you will have to use a profiler

• Trace java application at runtime

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I don't believe you can suddenly debug if it's not compiled with the -g option. Your only option is to recompile and redeploy. But once it's in place you can debug at will.