title: How to create jar file from existing jar file?
body: <p>I have not worked on java till now....
  But i need to include the jar file into my project.</p>
  
  <p>I have one jar created already with me. 
  But i need to update this jar file.
  I don't have source of those project.</p>
  
  <p>It has folder structure like follow</p>
  
  <pre><code>1. folder which has .class file.
  2. com folder
  3. de folder
  4. META-INF folder contains MANIFEST.INF file and Maven folder
  5. org folder
  6. config.properties
  7. abc.builds.properties
  </code></pre>
  
  <p>I need to update <code>config.properties</code> and create new jar file.</p>
  
  <p>Can anybody help me in this?</p>