equals, hashcode

public class Student {

		private int studentNum;
		
		private String studentName;
		
		public Student(int studentNum, String studentName) {
			this.studentNum = studentNum;
			this.studentName = studentName;
		}

		@Override
		public String toString() {
			return studentNum + "," + studentName;
		}

		
		@Override
		public boolean equals(Object obj) {
			if(obj instanceof Student) {
				Student std = (Student) obj;
				if(this.studentNum == std.studentNum)
					return true;
				else return false;
			}
			return false;
		}

		
		@Override
		public int hashCode() {
			return studentNum;
		}

 public class EqualsTest {

public static void main(String[] args) {

	Student std1 = new Student(100,"Lee");
	Student std2 = new Student(100,"Lee");
	
	System.out.println(std1 == std2);
	System.out.println(std1.equals(std2));
	
	System.out.println(std1.hashCode());
	System.out.println(std2.hashCode());