import java.util.regex.Pattern;
public class MyClass {
public static void main(String args[]) {
Pattern pattern = Pattern.compile("\\d{5}");
String s = "12345";
System.out.println(pattern.matcher(s).matches());
s = "1234";
System.out.println(pattern.matcher(s).matches());
s = "123456";
System.out.println(pattern.matcher(s).matches());
}
}
/*
run:
true
false
false
*/