Question

When my application run . I got a message says :

Ping: Timed out waiting for signal from JVM.
The JVM was launched with debug options so this may be because the JVM
is currently suspended by a debugger.  Any future timeouts during this
JVM invocation will be silently ignored.

What does that mean? It seems it will block any web request from outside? because when I upload a file to it, it failed. help me .

Answer 1

When debugging code, one would usually set breakpoints in it in order to break the execution of the program at some point. When the JVM encounters such breakpoint it suspends execution, and waits for the debugger to go further (step into / step over / step out / etc).

If you have an UI Debugger (like Eclipse) attached to your process, you can control the execution flow from there, watch variable values etc.

The message you’re seeing, simply says, that the timeout you got, may be simply the result of such situation, and is shown by the Java Service Wrapper, as described here:

The Wrapper will decide that the JVM is using a debugger if the wrapper.java.command property is set to “jdb” or “jdb.exe” or if one of the wrapper.java.additional.<n> properties is set to “-Xdebug”.

So it seems you are starting your app using Java Service Wrapper in debug mode, and when some of the timeouts expire, it warns you with the attached message.