how to Create a Java Package from MATLAB Code?

Anyone know why I'm getting an error with this code ? I'm stumped thanks:D?

• package MainPackage; import static org.lwjgl.opengl.GL11.GL_COLOR_BUFFER_BI… import static org.lwjgl.opengl.GL11.GL_MODELVIEW; import static org.lwjgl.opengl.GL11.GL_PROJECTION; import static org.lwjgl.opengl.GL11.GL_QUADS; import static org.lwjgl.opengl.GL11.glBegin; import static org.lwjgl.opengl.GL11.glClear; import static org.lwjgl.opengl.GL11.glEnd; import static org.lwjgl.opengl.GL11.glLoadIdentity; import static org.lwjgl.opengl.GL11.glMatrixMode; import static org.lwjgl.opengl.GL11.glOrtho; import static org.lwjgl.opengl.GL11.glVertex2i; import org.lwjgl.LWJGLException; import org.lwjgl.input.Keyboard; import org.lwjgl.input.Mouse; import org.lwjgl.opengl.Display; import org.lwjgl.opengl.DisplayMode; ; public class Main { public static enum State{ INTRO, MAIN_MENU, GAME; } public State state = State.INTRO; public Main() { try { Display.setDisplayMode(new DisplayMode(640, 480)); Display.setTitle("Maths"); Display.create(); } catch (LWJGLException e) { e.printStackTrace(); } // Initialization code OpenGL glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0, 640, 480, 0, 1, -1); glMatrixMode(GL_MODELVIEW); /*MAIN STUFF*/ while (!Display.isCloseRequested()) { // Render glClear(GL_COLOR_BUFFER_BIT); if(Menu.isInBounds = true && Mouse.isButtonDown(0)){ Display.destroy(); System.exit(0); } Menu.draw(); if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)… { Display.destroy(); System.exit(0); } int mousex = Mouse.getX(); int mousey = 480 - Mouse.getY(); //TESTING JUST PRINTS X & Y if(Mouse.isButtonDown(0) ) System.out.println("X : " + mousex + "|| Y :" + mousey); Display.update(); Display.sync(60); } // auto destroy if error across Display.destroy(); } /* end of constructor */ public static void main(String[] args) { new Main(); Menu.draw(); } } // Menu Class package MainPackage; import static org.lwjgl.opengl.GL11.GL_COLOR_BUFFER_BI… import static org.lwjgl.opengl.GL11.GL_MODELVIEW; import static org.lwjgl.opengl.GL11.GL_PROJECTION; import static org.lwjgl.opengl.GL11.GL_QUADS; import static org.lwjgl.opengl.GL11.glBegin; import static org.lwjgl.opengl.GL11.glClear; import static org.lwjgl.opengl.GL11.glEnd; import static org.lwjgl.opengl.GL11.glLoadIdentity; import static org.lwjgl.opengl.GL11.glMatrixMode; import static org.lwjgl.opengl.GL11.glOrtho; import static org.lwjgl.opengl.GL11.glVertex2i; import org.lwjgl.input.Mouse; import org.lwjgl.opengl.Display; public class Menu { public Menu(){ glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0, 640, 480, 0, 1, -1); glMatrixMode(GL_MODELVIEW); } public static int x1; public static int x2; public static int y1; public static int y2; static void draw(){ x1 = 170; x2 = 470; y1 = 200; y2 = 250; glBegin(GL_QUADS); glVertex2i(x1, y1); // Upper-left glVertex2i(x2, y1); // Upper-right glVertex2i(x2, y2); // Bottom-right glVertex2i(x1, y2); // Bottom-left glEnd(); } static boolean isInBounds; boolean isInBounds(int mousex, int mousey){ if(mousex > x1 && mousex < x2 && mousey > y1 && mousey < y2){ return true; } else{ return false; } } } // it runs fine but the x & y wont print out and when i close it a get the following error Exception in thread "main" java.lang.NullPointerException at org.lwjgl.opengl.GL11.glBegin(GL11.java:… at MainPackage.Menu.draw(Menu.java:40) at MainPackage.Main.main(Main.java:86)

• Answer:

  According to what it says, check line 86 in Main.java. However without full use of all import statements, we cannot see what you are trying to do.