How to check if a string is numeric

To check if a string is numeric in Java, you can use the isDigit method of the Character class to check if each character in the string is a digit.

Here's an example of how you might do this:

String str = "12345";

boolean isNumeric = true;
for (int i = 0; i < str.length(); i++) {
    if (!Character.isDigit(str.charAt(i))) {
        isNumeric = false;
        break;
    }
}

if (isNumeric) {
    System.out.println("The string is numeric.");
} else {
    System.out.println("The string is not numeric.");
}

In this example, the charAt method is used to get the character at a specific index in the string, and the isDigit method is used to check if the character is a digit. If any character is not a digit, the isNumeric variable is set to false and the loop is terminated.

After the loop, the isNumeric variable is checked, and the appropriate message is printed to the console.