How to remove duplicate objects in a List without equals/hashcode?

Question

I have to remove duplicated objects in a List. It is a List from the object Blog that looks like this:

public class Blog {
    private String title;
    priv         


        

Answer 1

    import java.util.ArrayList;

    import java.util.HashSet;

    class Person

{
    public int age;
    public String name;
    public int hashCode()
    {
       // System.out.println("In hashcode");
        int hashcode = 0;
        hashcode = age*20;
        hashcode += name.hashCode();
        System.out.println("In hashcode :  "+hashcode);
        return hashcode;
    }
     public boolean equals(Object obj)
        {
            if (obj instanceof Person)
                {
                    Person pp = (Person) obj;
                    boolean flag=(pp.name.equals(this.name) && pp.age == this.age); 
                    System.out.println(pp);
                    System.out.println(pp.name+"    "+this.name);
                    System.out.println(pp.age+"    "+this.age);
                    System.out.println("In equals : "+flag);
                    return flag;
                }
                else 
                    {
                    System.out.println("In equals : false");
                        return false;
                    }
         }
    public void setAge(int age)
    {
        this.age=age;
    }
    public int getAge()
    {
        return age;
    }
    public void setName(String name )
    {
        this.name=name;
    }
    public String getName()
    {
        return name;
    }
    public String toString()
    {
        return "[ "+name+", "+age+" ]";
    }
}
class ListRemoveDuplicateObject 
{
    public static void main(String[] args) 
    {
        ArrayList al=new ArrayList();

            Person person =new Person();
            person.setName("Neelesh");
            person.setAge(26);
            al.add(person);

            person =new Person();
            person.setName("Hitesh");
            person.setAge(16);
            al.add(person);

            person =new Person();
            person.setName("jyoti");
            person.setAge(27);
            al.add(person);

            person =new Person();
            person.setName("Neelesh");
            person.setAge(60);
            al.add(person);

            person =new Person();
            person.setName("Hitesh");
            person.setAge(16);
            al.add(person);

            person =new Person();
            person.setName("Mohan");
            person.setAge(56);
            al.add(person);

            person =new Person();
            person.setName("Hitesh");
            person.setAge(16);
            al.add(person);

        System.out.println(al);
        HashSet al1=new HashSet();
        al1.addAll(al);
        al.clear();
        al.addAll(al1);
        System.out.println(al);
    }
}

output

[[ Neelesh, 26 ], [ Hitesh, 16 ], [ jyoti, 27 ], [ Neelesh, 60 ], [ Hitesh, 16 ], [ Mohan,56 ], [ Hitesh, 16 ]]
In hashcode : -801018364
In hashcode : -2133141913
In hashcode : 101608849
In hashcode : -801017684
In hashcode : -2133141913
[ Hitesh, 16 ]
Hitesh Hitesh
16 16
In equals : true
In hashcode : 74522099
In hashcode : -2133141913
[ Hitesh, 16 ]
Hitesh Hitesh
16 16
In equals : true
[[ Neelesh, 60 ], [ Neelesh, 26 ], [ Mohan, 56 ], [ jyoti, 27 ], [ Hitesh, 16 ]]