## Troubleshooting jMonkeyEngine3 SDK

### Specifying the JDK location

You should install the JDK (the one from Oracle, not OpenJDK) first, and then the jMonkey SDK. If jMonkeyEngine SDK cannot find a valid JDK although you have it installed, then you have to specify the location manually.

1. Go to your jMonkeyEngine SDK installation directory.
   Mac users right-click jMonkeyApplication.app (which actually is a directory) in the Finder and select "Show package contents".
2. Navigate to the `etc` directory.
   Mac users navigate to `Contents/Resources/jmonkeyplatform/etc/`.
3. Open the file `jmonkeyplatform.conf` in a text editor.
4. Uncomment the following line and enter the path to the JDK:

       jdkhome="/path/to/jdk"

### Graphics Card Driver

On Windows and Linux make sure you have the latest driver installed. Make sure its the one supplied by the card manufacturer and not just the OS-default one.

### Stability / Graphics issues

On some Linux and Windows systems, the SDK might perform unstable and quit with native VM crashes or "x errors". There are a few things one can try to remedy those issues.

#### Heavyweight Canvas

First of all theres the new ???OpenGL??? settings page in the SDK global settings where you can enable the "heavyweight" canvas, which solved some issues for some people. The settings panel can be found under Tools???Options on Windows and Linux and in the main menu (or by pressing Apple-Comma) for MacOSX.

If you cannot start the SDK, edit the file `config/Preferences/com/jme3/gde/core.properties` in the SDK settings folder (see above). If it doesn't exist, create the file including all folders. Add the line `use_lwjgl_canvas=true`. To try OpenGL1 compatibility mode (works for both canvas settings) add `use_opengl_1=true`.

#### Look and Feel

The OS-built-in look and feel might cause issues, you can change the LAF by using the appropriate command line switch (or add it to the [app folder]/etc/jmonkeyplatform.conf file, without the "- -" prefix).

    --laf javax.swing.plaf.metal.MetalLookAndFeel

#### Compiz

Compiz on Linux might cause issues, if you set its rendering quality to "medium" these should go away. * Appearance???Set Special effects to ??? ???Medium???

### Updating problems

If you have problems updating the SDK, try deleting all files from `jmonkeyplatform/update/download` and/or `[settings folder]/update/download` depending on your system (see below for the settings folder location).

### Preferences and Settings

To completely remove and/or reinstall the SDK it is vital that the settings folder is deleted too. The location can be seen through the "about" menu and is as following for the different OS's:

- Windows: `C:\Users\<username>\AppData\Roaming\.jmonkeyplatform`
- Windows (alt): `C:\Users\<username>\.jmonkeyplatform\`
- MacOSX: `/Users/<username>/Library/Application Support/jmonkeyplatform`
- Ubuntu: `/home/<username>/.jmonkeyplatform`

### Getting error messages and reporting issues

When an exception happens in the SDK, a small warning sign appears in the lower right corner of the main window. Double-click it to open a window that allows you to see the exception stack trace. When posting about issues in the forum, always post the stack trace along with a description of what happens and how it can be reproduced.

### Known Issues

For a list of known issues and possible workarounds see the following link:

documentation, tool, sdk, faq

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