I am a new programmer in Java and while programming I faced the following problem. I am trying to use switch statement on String but it gives compilation error. If any one suggest me how to use String in switch-case statement , it will be helpful to me.

You can only switch on integer constants (static final int) or literals.

you would have to covert the string to char
and you would use single quotes, example:

case 'x':

i think this kinda blows too but what are you going to do?

thank u paradox.
But my purpose is not a single character. My requirement is String such as "black" "blue" etc.

like I said, you can't...
You could create a Map with those Strings as keys and integer values indexing an array of integer constants as values which you can then use as indices for the switch.
Easier to use a series of if ("black".equals(blah)) ... instead.

Was doing a research about it too. Got a simple solution, don't know if it is the best.

The String Class has a hashCode method that return the String hashcode (int) so u can do as this:

String name = "Victor";

switch (name.hashcode()) {
case "Victor".hashCode() : System.out.println("Name is Victor");
break;
case "Paul".hashCode() : System.out.println("Name is Paul");
break;
default : System.out.println("Default");
}

That MIGHT work but doesn't have to.
It all depends on the implementation of the hashcode method, which isn't guaranteed to return a unique number for each possible input.
So more than one String can yield the same hashcode.
And even if it works it's a very dirty hack.

Use enums instead.

Said that I didn't know if it was the best. Two words can really return the same hashCode, but you agree that the odds of this happening are very exceptional, don't you?

You can do too a hashCode compare of the words choosed before.

Don't understand how you are thinking about using Enum. Can you explain more ?

The odds are impossible to gauge without a thorough analysis of the algorithm used.
It is however extremely easy to provide a technically correct hashCode implementation that ALWAYS returns the exact same value, so you should NEVER rely on hashCode to be even remotely unique.

As to Enums, read up on those. You can switch on them as well as on integer constants.

Took me some time to understand how to do this with enum... but still didn't get how it can help with Strings.

Example that I found.

public enum Operation {
PLUS, MINUS, TIMES, DIVIDE;

// Do arithmetic op represented by this constant
double eval(double x, double y){
switch(this) {
case PLUS: return x + y;
case MINUS: return x - y;
case TIMES: return x * y;
case DIVIDE: return x / y;
}
throw new AssertionError("Unknown op: " + this);
}
}

Example using it:

public class Teste {
public static void main(String args[]) {
System.out.println(Operation.PLUS.eval(7,8));
System.out.println(Operation.MINUS.eval(7,8));
System.out.println(Operation.TIMES.eval(7,8));
System.out.println(Operation.DIVIDE.eval(7,8));
}
}