Prototype for a game engine based on JSON and Reflection using Processing

Game.pde

import java.lang.reflect.*;

import java.util.Map;
import java.util.Map.Entry;

int availableIndex = 0;

int generateID() {
  return availableIndex++;
}

class Game {
  PApplet parent;
  ArrayList<Entity> entities = new ArrayList<Entity>();
  Map<String, Method> systems = new HashMap<String, Method>();
  Game(PApplet parent) {
    this.parent = parent;
  }
  
  void add(Entity e) {
   entities.add(e); 
  }

  void addComponent(Entity e, String name, String comp) {
    Method commandMethod;
    try {
      commandMethod = parent.getClass().getMethod(name, 
      new Class[] { 
        Entity.class
      }
      );
    } 
    catch (Exception ex) {
      // no such method, or an error.. which is fine, just ignore
      commandMethod = null;
      PApplet.println("Please implement a " + name
        + "(Entity) method in your main sketch if you want to change "+ name + " properties");
    }
    if (commandMethod != null) {
      systems.put(name, commandMethod);
      
    }
    e.setComponent(name, comp);
  }

  void run() {
    for (Entry<String, Method> entry : systems.entrySet ()) {
      String compName = entry.getKey();
      Method m = entry.getValue();
      try {
        for (Entity e : entities) {
          if (e.hasComponent(compName))
          m.invoke(parent, e);
        }
      } 
      catch (Exception e) {
        // TODO Auto-generated catch block
        println("ahh");
      }
    }
  }
}

class Entity {
  public int id;
  
  JSONObject components = new JSONObject();
  public Entity() {
    id = generateID();
    components.setInt("id", id);
  }


  @Override
    public String toString() {
    return components.toString();
  }

  public void setComponent(String name, String json) {
    JSONObject newComp = JSONObject.parse(json);
    components.setJSONObject(name, newComp);
  }

  public boolean hasComponent(String comp) {
    return components.hasKey(comp);
  }

  public JSONObject getComponent(String comp) {
    return components.getJSONObject(comp);
  }
}