Java error - cannot find library in java.library.path?

Question

I am getting a error message like this:

The library libraryname.dll could not be loaded by Windows. Make sure that the library is in you Path environment variable. Exception in thread "main" java.lang.UnsatifiedLinkError: no libraryname in java.library.path.

This error is from me trying to run a jar file on Windows XP via cmd. I am wondering, where exactly is java.library.path? I've already added C:\Program Files\Java\jdk1.6.0_26 to my PATH but it still gives me the error. How would you go about debugging this?

Thanks.

Exact name? What do you mean? And how is it important? Thanks. — O_O, Aug 25 '11 at 19:12
@Thorbjørn the exact name is not important, the path to the directory where it exists is enough — Suraj Chandran, Aug 25 '11 at 19:14
PATH and library path are two different things. Can you post some example code that exhibits the problem? — jt., Aug 25 '11 at 19:14
Was the original error text "The library __libraryname__.dll could not..."? — Thorbjørn Ravn Andersen, Aug 25 '11 at 19:14

score 9 · Accepted Answer · edited Apr 23 '14 at 19:46

9

You can simply pass java.library.path as a system property as shown below:

java -Djava.library.path=<path_to_dll> <main_class>

First you need to find out where the libraryname.dll is and add it above in "path_to_dll".

edited Apr 23 '14 at 19:46

Greg Dubicki

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answered Aug 25 '11 at 19:06

Suraj Chandran

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What is the supposed to include? – O_O Aug 25 '11 at 19:11
The class that contains the main() method i.e. the entry point of the program – Suraj Chandran Aug 25 '11 at 19:12
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Worked for me as jna.library.path – mvmn Oct 14 '16 at 13:22

score 4 · Answer 2 · edited May 23 '17 at 12:32

4

The error is basically saying it cannot find your native libraries. Java tries to locate your library by looking into java.library.path property

It's an System environment that you need so Java can find your native libraries when you run your application. Several ways to do it:

Use java -Djava.library.path=[path to your library] when running your program

From the code you could also do.


System.setProperty( "java.library.path", "/path/to/libs" );

Set it up from your IDE. An example for Eclipse can be found in this SO question How to set java.library.path from eclipse

EDIT: A good comment below pointed out that #2 will not working 100% because you might not set this prior to calling getProperty(). Missed that point and thanks for pointing that out.

edited May 23 '17 at 12:32

Community

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answered Aug 25 '11 at 19:06

momo

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The second option you suggested does not work for the 'java.library.path' property. See: http://stackoverflow.com/questions/5419039/is-djava-library-path-equivalent-to-system-setpropertyjava-library-path – Jesse Webb Aug 25 '11 at 19:14
Well it doesn't work all the time. But if he sets it prior to getProperty(), I think it will work. Good point that I should mention in my answer and accepting the down vote for missing that – momo Aug 25 '11 at 19:16
The question is to get clarification on library.path and we should provide him the info of what is possible. I agree that it is not a good practice to set it up from the code. +1 for that comment – momo Aug 25 '11 at 19:24
It is not a matter of good practice, you *cannot* set that specific property from code. The property is loaded as part of the JVM initialization and the value is cached; changing the property programatically will have no effect. – Jesse Webb Aug 26 '11 at 19:16

Java error - cannot find library in java.library.path?

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