you should always use EQUALS when comparing strings.
A String is an OBJECT, when doing String == String, you are asking computer to check if they are the same 'object'.
for example:
String cat = "meow";
String tiger = "meow";
System.out.print(cat == tiger);
RETURNS: True.
String turtle = "";
//turtles are quiet.
String cat = turtle + "meow";
String tiger = "meow";
System.out.print(cat == tiger);
RETURNS: False.
The first example uses the same reference to "meow" both times while in the 2nd example the computer doesnt do this, and the objects dont match.
Just use cat.equals(tiger)
good luck