How to run Java my project with eclipse
<p>I have started learning Java and I have 1 issue:</p>

<p>I write a simple class and it runs and everything's fine.
I took all the project from my Laptop to my other computer and from Eclipse I choose "File --> Open File" and choose my .java file.</p>

<p>When I try to run my program this windows pop up:</p>

<p><img src="http://i.stack.imgur.com/8CM4V.jpg" alt="enter image description here"></p>

<p>and after trying both option nothing happen.</p>

<p>How can I run my program and what is the problem ?</p>
