Java – Need help with Java string issues

I am developing a programmable calculator in Android. I take user input as a sequence of characters and then convert it to a string. But before putting them on the stack, I have to check if the input is an integer or a symbol.

I’m basically from a C++ background. So I had trouble finding the right features to do the job. Any help would be appreciated.

Two possible solutions:

1. You can create a regex to check if your string is a number
2. You can try extracting its integer value using the following methods
   Integer.valueOf() , and catch the exception [ NumberFormatException ] thrown – If it’s not
   Number.

The first is most likely to be more efficient than the second