My Hindi Forum

My Hindi Forum (http://myhindiforum.com/index.php)
-   Tech Talks (http://myhindiforum.com/forumdisplay.php?f=20)
-   -   differences between == and .equals() (http://myhindiforum.com/showthread.php?t=59)

javaguru 22-12-2009 08:13 PM
differences between == and .equals()
 
What are the differences between == and .equals() in java ?

javaguru 22-12-2009 08:14 PM
Quote:
Originally Posted by javaguru (Post 118)
What are the differences between == and .equals() in java ?
The == operator compares two objects to determine if they are the same object in memory i.e. present in the same memory location. It is possible for two String objects to have the same value, but located in different areas of memory.

== compares references while .equals compares contents. The method public boolean equals(Object obj) is provided by the Object class and can be overridden. The default implementation returns true only if the object is compared with itself, which is equivalent to the equality operator == being used to compare aliases to the object. String, BitSet, Date, and File override the equals() method. For two String objects, value equality means that they contain the same character sequence. For the Wrapper classes, value equality means that the primitive values are equal.

javaguru 22-12-2009 08:15 PM
Code:
public class EqualsTest {

        public static void main(String[] args) {

                String s1 = “abc”;
                String s2 = s1;
                String s5 = “abc”;
                String s3 = new String(”abc”);
                String s4 = new String(”abc”);
                System.out.println(”== comparison : ” + (s1 == s5));
                System.out.println(”== comparison : ” + (s1 == s2));
                System.out.println(”Using equals method : ” + s1.equals(s2));
                System.out.println(”== comparison : ” + s3 == s4);
                System.out.println(”Using equals method : ” + s3.equals(s4));
        }
}

javaguru 22-12-2009 08:16 PM
Quote:
Originally Posted by javaguru (Post 120)
Code:
public class EqualsTest {

        public static void main(String[] args) {

                String s1 = “abc”;
                String s2 = s1;
                String s5 = “abc”;
                String s3 = new String(”abc”);
                String s4 = new String(”abc”);
                System.out.println(”== comparison : ” + (s1 == s5));
                System.out.println(”== comparison : ” + (s1 == s2));
                System.out.println(”Using equals method : ” + s1.equals(s2));
                System.out.println(”== comparison : ” + s3 == s4);
                System.out.println(”Using equals method : ” + s3.equals(s4));
        }
}

Output
== comparison : true
== comparison : true
Using equals method : true
false
Using equals method : true


All times are GMT +5. The time now is 12:17 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
MyHindiForum.com is not responsible for the views and opinion of the posters. The posters and only posters shall be liable for any copyright infringement.