Java Sets Unique?

test1.java

package com.company;

import java.util.HashSet;
import java.util.Set;

public class Main {

    public static class Test {
        private String blah;

        public Test(String blah) {
            this.blah = blah;
        }

        @Override
        public String toString() {
            return "Test{" + "blah='" + blah + '\'' + '}';
        }

        public String getBlah() {
            return blah;
        }

        public void setBlah(String blah) {
            this.blah = blah;
        }
    }

    public static void main(String[] args) {
        Set<Test> set = new HashSet<>();
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));

        for (Test test : set) {
            System.out.println(test);
        }
    }
}




// OUTPUT:
Test{blah='ABC'}
Test{blah='ABC'}
Test{blah='ABC'}
Test{blah='ABC'}
Test{blah='ABC'}
Test{blah='ABC'}

test2.java

package com.company;

import java.util.HashSet;
import java.util.Set;

public class Main {

    public static class Test {
        private String blah;

        public Test(String blah) {
            this.blah = blah;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;

            Test test = (Test) o;

            return blah.equals(test.blah);
        }

        @Override
        public int hashCode() {
            return blah.hashCode();
        }

        @Override
        public String toString() {
            return "Test{" + "blah='" + blah + '\'' + '}';
        }

        public String getBlah() {
            return blah;
        }

        public void setBlah(String blah) {
            this.blah = blah;
        }
    }

    public static void main(String[] args) {
        Set<Test> set = new HashSet<>();
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));
        set.add(new Test("ABC"));

        for (Test test : set) {
            System.out.println(test);
        }
    }
}


// OUTPUT:

Test{blah='ABC'}