A. How to use OpenGL/Other libraries
1. The Processing library ('core.jar') does not contain the functionality for using the OpenGL context. Therefore another part of the framework has to be imported. The library files named 'gluegen-rt.jar', 'jogl.jar' and 'opengl.jar' are located: Processing/libraries/opengl/library/ (WIN) Processing.app/Contents/Resources/Java/libraries/opengl/library/ (OS X). Like the standard Processing library ('core.jar') the libraries for OpenGL have to be a part of the project build path. Copy the libraries into the 'lib' folder of the project. Right-click on the files in the Package Explorer of eclipse and select 'Build Path' → 'Add to Build Path'.
2. The above mentioned specific operating system files are located in the same directory as the 'jogl.jar'. Create a folder named 'jni' in your project and copy all .jnilib documents (Mac OS X) into it. Processing version 1.0.7 contains 4 of them (libgluegen-rt.jnilib, libjogl_awt.jnilib, libjogl_cg.jnilib, libjogl.jnilib).
3. Last action is to link the 'gluegen-rt.jar' and the 'jogl.jar' library with their native interfaces. Select one of the them in the Package Explorer and right-click to open the context menu. Afterwards choose 'Build Path' → 'Configure Build Path'. A window opens where all library files are listed. Each library is represented by a node that can be opened and closed. Open the nodes of both libs and select the field 'Native library location', press 'Edit' on the right and set the 'jni' folder of your project. Confirm all changes and the project setting are ready for OpenGL.
From http://www.creativecoding.org/en/beyond/p5/eclipse_as_editor#using_opengl_other_libraries