ImmutableBean

ImmutableBean.java

public final class ImmutableBean{
  public final String name;
  public final Integer age;
  
  public ImmutableBean(String name, Integer age){
    if(name == null || name.length < 1 || age == null || age < 0)
      throw new IllegalArgumentException("name must be set and age must be 0 or over");
      
    this.name = name;
    this.age = age;
  }
 
  // implement equals, toString and hashCode as well! 
}