import java.util.Hashtable;    // Java lookup mechanism based on key

public class Bean {            // some business object
  public String ID;            // primary key
  public static Hashtable beans = new Hashtable();  // find bean keyed on ID
         // static: just one hashtable
  public Bean(String ID) {
    this.ID = ID;        // store ID in public String
    beans.put(ID,this);  // put itself into the hashtable using primary key
  }
  public String toString() {  // printable business object
    return (ID);
  }
}