Question

I am using following code to check if the String is empty

if( !Index2.toString().isEmpty()){
  ....
}

But I run into following error

java.lang.NullPointerException

Answer 1

Your Index2 variable has null value. That’s why you get the error. Specifically, the error is here:

Index2.toString()

Assuming your Index2 variable is different from null, your code will work. In order to make your code to work, you can validate that your Index2 is different from null or add a try/catch block that handles NullPointerException.

First way:

if( Index2 != null && !Index2.toString().isEmpty()){
    //...
}

Second way:

try {
    if( !Index2.toString().isEmpty()){
      //...
    }
} catch (NullPointerException npe) {
    //handle the Exception...
}

IMHO I would use the first way.