# Check if a String contains a number
```Java
String s = "32";
try {
Integer.parseInt(s);
System.out.println(s + " is an integer");
} catch (NumberFormatException nfe) {
System.err.println(s + " is not an integer");
}
```
# Validate a number
```java
Scanner scan = new Scanner(System.in);
int age = 0;
do {
System.out.println("Enter an age between 11 and 18");
try {
age = scan.nextInt();
} catch (InputMismatchException ex) {
System.out.println("Must enter integer");
scan.nextLine();
}
} while (age < 11 || age > 18);
System.out.println("Age is " + age);
```