PK(BigInteger bint, DateTime dt) {     this.id = bint;     this.effectiveTime = dt; }  /** getters and setters **/ public DateTime getEffectiveTime(){return effectiveTime;} public void setEffectiveTime(DateTime ad){effectiveTime=ad;}  public void setId(BigInteger id) {this.id = id;} public BigInteger getId() {return id;}  @Override public boolean equals(Object obj) {      if (this == obj) return true;     if (obj == null) return false;     if (getClass() != obj.getClass()) return false;     final 