title: How to call java classes of a compiled jar file within android studio?
body: <p>Hello StackOverflow folks,</p>
  
  <p>I have a jar file of java classes. I added this jar file to my android studio project under folder <code>/libs</code>. Now, what I want to do is use those classes within the jar file in <code>MainActiviy.java</code>. I just do not know how.</p>
  
  <p>Some details:
  My jar file is named: <code>zombi.jar</code>.</p>
  
  <p>The class within the jar file to call is named: <code>COMBI.class</code></p>
  
  <p>I tried the following:</p>
  
  <p>In <code>MainActivity.java</code>, I wrote:</p>
  
  <pre><code>// declared class variable
  private COMBI mCOMBI;
  </code></pre>
  
  <p>Then, in OnCreate method, I wrote:</p>
  
  <pre><code>mCOMBI = new COMBI();
  //to start calling method COMBIStart to launch the command-line system
  mCOMBI.COMBIStart(); 
  </code></pre>
  
  <p>I actually called the classes as I would in normal Java. I think Android uses special java code that looks like java, but I don't know how to use them.</p>
  
  <p>I could not get the code to work. 
  Can you help me? </p>