Ever needed to check if a string in Java is a valid integer before you use it in calculations? In this video, I walk you through two practical ways I use to validate string data so you can avoid those annoying NumberFormatException crashes. I start with a few clear test cases: a valid positive integer, a non-numeric string, a number with a decimal, and a negative integer. The goal is simple—write a method that correctly identifies only the valid integers. First, I show a basic try/catch approach where I attempt to parse the input and return true if parsing works, otherwise false when the exception is thrown. This is a quick and effective method if you just want to know whether something is “numeric” in a general sense. But I also highlight the catch: parsing as a double will return true for values like 98.7, which isn’t a strict integer. To fix that, I switch to a regex solution using a pattern like ^-?\d+$, which locks the check down to whole numbers only—no decimals, letters, spaces, or extra characters. The takeaway: use try/catch parsing for broad numeric validation, and use regex when you need strict integer-only input.