Check whether list of number is sequential or not
<p>I have quite a layman question about Java programming.</p>

<p>I would like to write a function to check whether a list of number is sequential or not.</p>

<p>Say [1, 2, 3, 4, 5], the function will return true,</p>

<p>but for [1, 3, 4, 9, 10], the function will return false.</p>

<p>Could anyone help me?</p>

<p>Thank so much!</p>
