I don't think you understand what are you asking about. The DLL is in an executable file format; this is not data you could "read" in any sensible way. OK, you can read it as a chunk of binary data and even parse the content, but it does not mean you can use it.
However, a DLL file may or may not contain some resources you could extract if that is what you are after.
Also, the native Windows DLL file is foreign to both .NET (speaking of C# projects) and Java. You can only use it in .NET via P/Invoke and in Java via JNI.
See:
http://en.wikipedia.org/wiki/PInvoke[
^],
http://en.wikipedia.org/wiki/JNI[
^].
—SA