protected void waitFor(boolean createdVal) {
        synchronized (createdLock) {
            while (created.get() != createdVal) {
                try {
                    createdLock.wait();
                } catch (InterruptedException ex) {}
            }
        }
    }
Accesses the listener that receives events related to this context.

@return the pre-existing instance
jme3-core/src/main/java/com/jme3/system/NullContext.java