@Override
    public int getFramebufferHeight() {
        glfwGetFramebufferSize(window, width, height);
        int result = height[0];
        return result;
    }
Returns the height of the framebuffer.

@return the height (in pixels)
jme3-lwjgl3/src/main/java/com/jme3/system/lwjgl/LwjglWindow.java