<p>I have a .jar file that i've placed in my D:\Coldfusion8\wwwroot\web-inf\lib\ directory.  The file is abcdef.jar</p>

<p>This is my first time doing this, not sure what the path should be in my createObject().</p>

<pre><code>&lt;cfset abcObj = createObject("java","com.abcdef") /&gt;
&lt;cfset result = acbObj.doStuff("123456") /&gt;
</code></pre>

<p>But when I run it, I get </p>

<pre><code>Object Instantiation Exception.
Class not found: com.vp4jo_b 
</code></pre>

<p>What am I missing in the path?</p>

Have you restarted the Coldfusion Service?
Even when in the class path, jars are only loaded at server start.
Info moved up from the comments:
Make sure the file is in the System class path, or in the one of the configured class paths of ColdFusion.
As for the class name parameter of
```
CreateObject()
```
: The class name starts within the jar. Open it like a .zip file and look at its structure. The dotted path mimics the folder structure, so if the Server still complains, you must be missing something in the dotted path.