package com.example;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class ClassUnit {
  public Integer id;
  public String name;
  public String enlistedOn;
  public String leftOn;

  public ClassUnit() {
    this.id = null;
    this.name = null;
    this.enlistedOn = null;
    this.leftOn = null;
  }

  public ClassUnit(
    Integer id,
    String name,
    String enlistedOn,
    String leftOn
  ) {
    this.id = id;
    this.name = name;
    this.enlistedOn = enlistedOn;
    this.leftOn = leftOn;
  }
}

@@ -348,23 +348,22 @@
 it(%0A    
-Integer
+String
  id,%0A   
@@ -439,16 +439,49 @@
 .id = id
+ == null ? null : new Integer(id)
 ;%0A    th

Rework a constructor