java.lang.NoClassDefFoundError when using third party library in Android application (Aviary SDK)
<p>This has been driving me absolutely crazy. There's 101 answers to this kind of problem scattered across Stack Overflow but nothing seems to work for me.</p>

<p>Here's the story:</p>

<ol>
<li>I downloaded the Aviary SDK (if that's relevant) and imported their library project into my workspace</li>
<li>I added their Library under Project -> Android -> Add.. and it's checked off there</li>
<li>The JAR (aviary-sdk.jar) containing the class that apparently is missing at runtime (com.aviary.android.feather.FeatherActivity) is listened under Android Dependencies in Project -> Java Build Path</li>
<li>The project builds correctly, but at runtime it throws a java.lang.NoClassDefFoundError when trying to launch this activity</li>
</ol>

<p>I've tried a bunch of things (checking and unchecking things in Order and Export, reordering things there, etc.) but nothing is taking. I also tried just manually including the JAR in the /libs folder, but this SDK depends on a bunch of other things in that library project (e.g. themes) and having the SDK referenced twice doesn't work either.</p>

<p>I'm completely stumped here. I've looked at all kinds of other answers and nothing seems to work. I'm starting to get the feeling that this method of referencing other libraries is no longer supported...?</p>

<p><strong>Edit</strong>: I've created a fresh Android project and reproduced the problem there, too. I suspect it has to be something stupid in my build environment:
<img src="http://i.stack.imgur.com/bdwL4.png" alt="aviary test app">
<img src="http://i.stack.imgur.com/1fSCN.png" alt="aviary test app project properties">
<img src="http://i.stack.imgur.com/H9uq0.png" alt="aviary test app build path"></p>
