override equals java

11.	public class Test
22.	{
33.		private int num;
44.		private String data;
55.
66.		public boolean equals(Object obj)
77.		{
88.			if(this == obj)
99.				return true;
1010.			if((obj == null) || (obj.getClass() != this.getClass()))
1111.				return false;
1212.			// object must be Test at this point
1313.			Test test = (Test)obj;
1414.			return num == test.num &&
1515.			(data == test.data || (data != null && data.equals(test.data)));
1616.		}
1726.		// other methods
1827.	}

1class Complex { 
2
3	private double re, im; 
4
5	public Complex(double re, double im) { 
6		this.re = re; 
7		this.im = im; 
8	} 
9
10	// Overriding equals() to compare two Complex objects 
11	@Override
12	public boolean equals(Object o) { 
13
14		// If the object is compared with itself then return true 
15		if (o == this) { 
16			return true; 
17		} 
18
19		/* Check if o is an instance of Complex or not 
20		"null instanceof [type]" also returns false */
21		if (!(o instanceof Complex)) { 
22			return false; 
23		} 
24		
25		// typecast o to Complex so that we can compare data members 
26		Complex c = (Complex) o; 
27		
28		// Compare the data members and return accordingly 
29		return Double.compare(re, c.re) == 0
30				&& Double.compare(im, c.im) == 0; 
31	} 
32} 
33
34// Driver class to test the Complex class 
35public class Main { 
36
37	public static void main(String[] args) { 
38		Complex c1 = new Complex(10, 15); 
39		Complex c2 = new Complex(10, 15); 
40		if (c1.equals(c2)) { 
41			System.out.println("Equal "); 
42		} else { 
43			System.out.println("Not Equal "); 
44		} 
45	} 
46} 
47