OpenJDK's JDK location

Question

I'm running Minecraft on a headless Linux server with OpenJDK. I've added a bunch too many mods and its lagging (even on my local network) without using too much CPU or memory (e.g. its lagging, but its still got resources it can use). So I'm pretty sure its a mod fault.

To save the hassle of removing/adding mods one by one to see whats causing the error, my research led me to VisualVM where you can profile the java application and see which entities are doing what and with what resources. With any luck it should point out the mod consuming the most resources, and the most ticks.

Given its a headless server, and VisualVM is a window/GUI application, I've successfully managed to get it running and passing the GUI back to my Windows client using X over SSH.

Trouble is now, that its telling me that I need to use JDK and not JRE. Which is fair enough. Except OpenJDK has JDK in its name, rendering all googling futile. I cannot for the life of me, find if JDK is included in OpenJDK, what its named, and where it may be located. The other problem is, most of the troubleshooting guides I find are for Windows, and dont help me find the JDK on linux.

As some background information, I'm running Debian, and I know OpenJDK's JRE is installed here: /usr/lib/jvm/java-7-openjdk-amd64/jre

Can someone tell me please, if JDK is in OpenJDK, or I need to install it as well? If I do need to install it, is there an OpenJDK equivelant for JDK? If its already included, can someone provide some tips on locating it, so I can point VisualVM at it instead of the JRE?

Answer 1

The OpenJDK has a JDK, but there is also a cut down version which is just the JRE. I would use locate javac and if it can't find it, you need to install the JDK.