Testprogramm

import java.util.* ;

class Entry
{
  private String name;
  private String number;

  // constructor
  public Entry( String n, String num )
  {
    name = n; number = num;
  }

  // methods
  public String getName()
  {
    return name ;
  }

  public String getNumber()
  {
    return number ;
  }

  @Override
  public boolean equals( Object other )
  {
    return getName().equals( ((Entry)other).getName() );
  }

  @Override
  public String toString()
  {
    return "Name: " + getName() + "; Number: " + getNumber() ;
  }

}

public class PhoneBookTest
{
  public static void main ( String[] args)
  {
    ArrayList<Entry> phone = new ArrayList<>();

    phone.add( new Entry( "Amy", "123-4567") );
    phone.add( new Entry( "Bob", "123-6780") );
    phone.add( new Entry( "Hal", "789-1234") );
    phone.add( new Entry( "Deb", "789-4457") );
    phone.add( new Entry( "Zoe", "446-0210") );

    // Look for Hal in phone. The indexOf() method uses the
    // equals(Object) method of each object in the list.

    Entry target = new Entry( "Hal", null );

    int spot = phone.indexOf( target ) ;

    System.out.println( "indexOf returns: " + spot ) ;
  }
}