OpenGL rendering with null exception crashes appliaction

[cansik]

Exception in thread "Thread-2" java.lang.NullPointerException
    at java.util.LinkedList.unlink(LinkedList.java:211)
    at java.util.LinkedList.remove(LinkedList.java:526)
    at processing.opengl.Texture.bufferUpdate(Texture.java:897)
    at processing.opengl.PGraphicsOpenGL.getTexture(PGraphicsOpenGL.java:6393)
    at processing.opengl.PGraphicsOpenGL$TexCache.getTexture(PGraphicsOpenGL.java:7426)
    at processing.opengl.PGraphicsOpenGL.flushPolys(PGraphicsOpenGL.java:2404)
    at processing.opengl.PGraphicsOpenGL.flush(PGraphicsOpenGL.java:2345)
    at processing.opengl.PGraphicsOpenGL.endDraw(PGraphicsOpenGL.java:1526)
    at ch.bildspur.visualpush.sketch.RenderSketch.draw(RenderSketch.java:137)
    at processing.core.PApplet.handleDraw(PApplet.java:2403)
    at processing.opengl.PSurfaceJOGL$DrawListener.display(PSurfaceJOGL.java:861)
    at jogamp.opengl.GLDrawableHelper.displayImpl(GLDrawableHelper.java:692)
    at jogamp.opengl.GLDrawableHelper.display(GLDrawableHelper.java:674)
    at jogamp.opengl.GLAutoDrawableBase$2.run(GLAutoDrawableBase.java:443)
    at jogamp.opengl.GLDrawableHelper.invokeGLImpl(GLDrawableHelper.java:1293)
    at jogamp.opengl.GLDrawableHelper.invokeGL(GLDrawableHelper.java:1147)
    at com.jogamp.newt.opengl.GLWindow.display(GLWindow.java:759)
    at com.jogamp.opengl.util.AWTAnimatorImpl.display(AWTAnimatorImpl.java:81)
    at com.jogamp.opengl.util.AnimatorBase.display(AnimatorBase.java:452)
    at com.jogamp.opengl.util.FPSAnimator$MainTask.run(FPSAnimator.java:178)
    at java.util.TimerThread.mainLoop(Timer.java:555)
    at java.util.TimerThread.run(Timer.java:505)