Java Collection How to - Compare elements in list and remove if some properties are the same

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Question

We would like to know how to compare elements in list and remove if some properties are the same.

Answer

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
//w  ww.ja  va 2  s.  c o  m
class Employee {
  private String name;
  private String address;
  private String phone;

  public Employee() {
    super();
  }

  public Employee(String name, String address, String phone) {
    super();
    this.name = name;
    this.address = address;
    this.phone = phone;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public String getAddress() {
    return address;
  }

  public void setAddress(String address) {
    this.address = address;
  }

  public String getPhone() {
    return phone;
  }

  public void setPhone(String phone) {
    this.phone = phone;
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((address == null) ? 0 : address.hashCode());
    result = prime * result + ((name == null) ? 0 : name.hashCode());
    result = prime * result + ((phone == null) ? 0 : phone.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    Employee other = (Employee) obj;
    if (address == null) {
      if (other.address != null)
        return false;
    } else if (!address.equals(other.address))
      return false;
    if (name == null) {
      if (other.name != null)
        return false;
    } else if (!name.equals(other.name))
      return false;
    if (phone == null) {
      if (other.phone != null)
        return false;
    } else if (!phone.equals(other.phone))
      return false;
    return true;
  }

  @Override
  public String toString() {
    return "Employee [name=" + name + ", address=" + address + ", phone="
        + phone + "]";
  }

}

public class Main {

  public static void main(String[] args) {

    Set<Employee> empSet = new HashSet<Employee>(populateList());

    for (Employee employee : empSet) {
      System.out.println(employee);
    }

  }

  public static List<Employee> populateList() {
    List<Employee> lsts = new ArrayList<Employee>();

    lsts.add(new Employee("A", "B", "123456"));
    lsts.add(new Employee("C", "E", "123685"));
    lsts.add(new Employee("D", "F", "1257456"));
    lsts.add(new Employee("D", "F", "196356"));
    lsts.add(new Employee("A", "B", "123456"));
    lsts.add(new Employee("A", "B", "123456"));
    lsts.add(new Employee("A", "B", "123456"));
    return lsts;

  }

}

The code above generates the following result.

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