@Override public boolean equals(Object otherObj){
  if (otherObj instanceof P2Model) {
    return content.equals(((P2Model)otherObj).content);
  }
 else {
    return false;
  }
}

@ Override public boolean equals ( Object otherObj ) { if ( otherObj instanceof P2Model ) { return content . equals ( ( ( P2Model ) otherObj ) . content ) ; } else { return false ; } }
two models are equal if all their fields are equal .
