package models;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.OneToMany;

import play.data.validation.MaxSize;
import play.data.validation.Required;
import play.db.jpa.Model;

@Entity
public class Track extends Model implements Comparable<Track>{
	@Required
	public String title;
	
	@Required
	@MaxSize(1)
	public Integer order;

	@OneToMany(mappedBy = "track")
	public List<Talk> talks = new ArrayList<Talk>();
	
	@Override
	public String toString(){
		return title;
	}

	@Override
	public int compareTo(Track other) {
		return order.compareTo(other.order);
	}
}

@@ -376,21 +376,20 @@
 lic 
-Integer order
+int position
 ;%0A%0A%09
@@ -517,16 +517,40 @@
 %09%09return
+ %22%5B%22 + position + %22%5D %22 +
  title;%0A
@@ -599,24 +599,26 @@
  other) %7B%0A%09%09
+//
 return order
@@ -642,13 +642,49 @@
 order);%0A
+%09%09return position - other.position;%0A
 %09%7D%0A%7D%0A

Rename "order" to "position" in the track object