NullPointerException with LWJGL 3 Initialization

java, lwjgl

Solution

The solution is to specify an absolute path for `java.library.path`, rather than a relative one.

On the LWJGL forums, there was a user with a similar problem (I found this by searching for the problematic line and doing some hunting on the forum). The relevant part of the conversation is:

lightbringer writes:

I think I figured it out. In LWJGLUtil.java I took out some code and ran it from my main()`. I got an

java.lang.UnsatisfiedLinkError: Expecting an absolute path of the library: lib/native\lwjgl.dll`

inside loadLibrary(). System.load() apparently needs an absolute path but you are passing it a relative path.

I tested with -Djava.library.path=E:\Dropbox\private\projects\solariad\redist\lib\native and this indeed did work as expected.

The root of the issue is LWJGL's use of `System.load()`, which is not problematic in itself, but it does requires an absolute path name to the libraries it loads (see source as well).

If you take a look at LWJGLUtil.java (although the version at the time of this writing does not correspond exactly to your stack trace) and `Sys.doLoadLibrary()`, you can see that it attempts to load libraries by going through all the path strings in `java.library.path`, appending the library name, and trying `System.load()` on those paths. Since `load()` requires an absolute path the implication is that `java.library.path` must contain the absolute path to the LWJGL libraries as well.

It is unfortunate that the root cause of the problem was muddled by the NPE but, you know, it's a hard knock life for us poor programmers!

Problem

Original source