Check if the input value is a number in Java

To check if the input value is a digit in Java, use the Character.isDigit() method.

We have a character to check.

char val = '5';

Now let's use the Character.isDigit() method.

if (Character.isDigit(val)) {
　　　System.out.println("Character is a digit!");
} else {
　　　System.out.println("Character is not a digit!");
}

Now let's see a complete example to check uppercase letters in Java.

Example

public class Demo {
　　　public static void main(String []args) {
　　　　　　System.out.println("Checking for digit...");
　　　　　　char val = '5';
　　　　　　System.out.println("Value: "+val);
　　　　　　if (Character.isDigit(val)) {
　　　　　　　　　System.out.println("Character is a digit!");
　　　　　　}else {
　　　　　　　　　System.out.println("Character is not a digit!");
　　　　　　}
　　　}
}

Output Result

Checking for digit...
Value:　5
Character is a digit!