Difference between == and .equals()?

Question

I am learning Java now. When I use == and .equals() for String comparisons, I am getting different results. But there is no compilation error. Can anyone explain the difference between these two operations?

Answer 1

• s1 == s2 compares string references; this is very rarely what you want.
• s1.equals(s2) compares the two character sequences; this is almost always what you want.

Answer 2

== tests for reference equality.

.equals() tests for value equality.

Example:

String fooString1 = new String("Java");
String fooString2 = new String("Java");

// false
fooString1 == fooString2;

// true
fooString1.equals(fooString2);

Note:

== handles null strings values.

.equals() from a null string will cause Null Pointer Exception

Answer 3

when == is used for comparision between String then it checks the reference of the objects. But when equals is used it actually checks the contents of the String. So for example

  String a = new String("ab");
  String b = new String("ab");
  if(a==b) ///will return false because both objects are stored on the different locations in memory

   if(a.equals(b)) // will return true because it will check the contents of the String

i hope this helps