How to validate if studentNo is a 11-digit no
<p>Good day!</p>

<p>I have a class Student with  attribute String studentNo</p>

<p>Using OO, how can I validate if the input is an 11-digit no.</p>

<p>I can do this:</p>

<pre><code>If(studentNo.length()&lt;11){

}
</code></pre>

<p>to validate.. but how can I determine if it is a number or not.</p>

<p>And what are the other methods on how can I do this validation.</p>

<p>Any help would be highly appreciated.
Thank you.</p>
