OnJava8-Examples/strings/IntegerMatch.java

// strings/IntegerMatch.java

public class IntegerMatch {
  public static void main(String[] args) {
    System.out.println("-1234".matches("-?\\d+"));
    System.out.println("5678".matches("-?\\d+"));
    System.out.println("+911".matches("-?\\d+"));
    System.out.println("+911".matches("(-|\\+)?\\d+"));
  }
}
/* Output:
true
true
false
true
*/