Wild guess: When you are comparing 2 variables, your actually passing the bits of the current variable your comparing. s2 has the bit representation value of the s1 with a value of "arit" and s3 has the bit representation value of the
string "arit" only..
When you are directly using a value (example: String j = "po"), i would recommend to use == for comparison and if you are actually comparing the string object (ex: String j = new String("po")), it would be advisable to use .equals() method (which is overriden from the object class).