collision - Error at GFX.java:37 -

i'm trying collision thought got apparently not when ran game got error.. annoying. i've come here :d :p anyway kept on getting error

exception in thread "awt-eventqueue-0" java.lang.nullpointerexception     @ com.shiny21.graphics.gfx.step(gfx.java:37)     @ com.shiny21.graphics.gfx.actionperformed(gfx.java:65)     @ javax.swing.timer.fireactionperformed(unknown source)     @ javax.swing.timer$dopostevent.run(unknown source)     @ java.awt.event.invocationevent.dispatch(unknown source)     @ java.awt.eventqueue.dispatcheventimpl(unknown source)     @ java.awt.eventqueue.access$200(unknown source)     @ java.awt.eventqueue$3.run(unknown source)     @ java.awt.eventqueue$3.run(unknown source)     @ java.security.accesscontroller.doprivileged(native method)     @ java.security.protectiondomain$1.dointersectionprivilege(unknown source)     @ java.awt.eventqueue.dispatchevent(unknown source)     @ java.awt.eventdispatchthread.pumponeeventforfilters(unknown source)     @ java.awt.eventdispatchthread.pumpeventsforfilter(unknown source)     @ java.awt.eventdispatchthread.pumpeventsforhierarchy(unknown source)     @ java.awt.eventdispatchthread.pumpevents(unknown source)     @ java.awt.eventdispatchthread.pumpevents(unknown source)     @ java.awt.eventdispatchthread.run(unknown source) 

i don't understand errors yet heres code gfx:

    package com.shiny21.graphics;  import java.awt.color; import java.awt.graphics; import java.awt.event.actionevent; import java.awt.event.actionlistener;  import javax.swing.jpanel; import javax.swing.timer;  import com.shiny21.framework.collision; import com.shiny21.players.playerb; import com.shiny21.players.playerr;  public class gfx extends jpanel implements actionlistener{      playerr red;     playerb blue;     collision col;      public gfx(){          red = new playerr(getx(), gety());         blue = new playerb(getx(), gety());          this.setfocusable(true);         this.requestfocus();          setbackground(color.black);          timer timer = new timer(1000 / 60, this);         timer.start();     }      public void step(){          col.collisionstep();         red.step();         blue.step();         //system.out.println("");      }      public void paintcomponent(graphics g){         super.paintcomponent(g);          //red         g.setcolor(color.red);         g.fillrect(red.getx(), red.gety(), 8, 8);          g.setcolor(color.white);         g.drawrect(red.getx()+20 - red.getsightw(), red.gety()+20 - red.getsighth(), red.getsightw(), red.getsighth());          //blue         g.setcolor(color.blue);         g.fillrect(blue.getx(), blue.gety(), 8, 8);          g.setcolor(color.green);         g.drawrect(blue.getx()+20 - blue.getsightw(), blue.gety()+20 - blue.getsighth(), blue.getsightw(), blue.getsighth());      }       public void actionperformed(actionevent ae) {         step();         repaint();     } } 

so heres collision code:

    package com.shiny21.framework;  import java.awt.rectangle;  import com.shiny21.players.playerb; import com.shiny21.players.playerr;  public class collision {      playerb blue;     playerr red;      public collision(){         collisionstep();     }      public void collisionstep(){         rectangle r1 = blue.getbounds();         rectangle r2 = red.getbounds();          if(r1.intersects(r2)){             blue.setdx(-1);             red.setdx(1);         }     } } 

edit 1:

i error

exception in thread "main" java.lang.nullpointerexception @ com.shiny21.framework.collision.<init>(collision.java:14) @ com.shiny21.graphics.gfx.<init>(gfx.java:25) @ com.shiny21.framework.game.main(game.java:18) 

i added collision class:

blue = new playerb(blue.getx(), blue.gety()); red = new playerr(red.getx(), red.gety()); 

your field col null , never set. line col.collisionstep();