If a jar is not placed in the libs folder the classes in jar file are not found
<p>I am using a thirdparty jar file in my android project. When I add the jar to the build paths, via eclipse project -> properties -> java build path -> Libraries -> add external jar.</p>

<p>The project compiles fine until that line of code runs which uses any class from that jar and I get class not found exception at runtime and the program crashes.</p>

<p>I solved it by copying the third party jar file to the libs folder of my project. The class not found exception goes away.</p>

<p>Question:
Can someone please shed some light why this is required and why does it not just work with a reference from the project properties despite the fact it compiles fine.. Why do I have to explicitly copy it to libs folder ?</p>
