code: public void update(int delta) {
  		if ((sprite == null) && (defaultImageName != null)) {
  			loadSystemParticleImage();
  		}
  		
  		removeMe.clear();
  		ArrayList emitters = new ArrayList(this.emitters);
  		for (int i=0;i<emitters.size();i++) {
  			ParticleEmitter emitter = (ParticleEmitter) emitters.get(i);
  			if (emitter.isEnabled()) {
  				emitter.update(this, delta);
  				if (removeCompletedEmitters) {
  					if (emitter.completed()) {
  						removeMe.add(emitter);
  						particlesByEmitter.remove(emitter);
  					}
  				}
  			}
  		}
  		this.emitters.removeAll(removeMe);
  		
  		pCount = 0;
  		
  		if (!particlesByEmitter.isEmpty())
  		{
  			Iterator it= particlesByEmitter.keySet().iterator();
  			while (it.hasNext())
  			{
  				ParticleEmitter emitter = (ParticleEmitter) it.next();
  				if (emitter.isEnabled()) {
  					ParticlePool pool = (ParticlePool) particlesByEmitter.get(emitter);
  					for (int i=0;i<pool.particles.length;i++) {
  						if (pool.particles[i].life > 0) {
  							pool.particles[i].update(delta);
  							pCount++;
  						}
  					}
  				}
  			}
  		}
  	}
docs: Update the system, request the assigned emitters update the particles
  
  @param delta The amount of time thats passed since last update in milliseconds