UnsatisfiedLinkError on System.loadLibrary() after adding the directory to java.library.path

Question

I would like to load the local library /opt/gurobi902/linux64/lib/libGurobiJni90.so within my Java IntelliJ Maven project on Ubuntu 19.10.

My first attempt was adding the environment variable LD_LIBRARY_PATH like this: export LD_LIBRARY_PATH="/opt/gurobi902/linux64/lib" (I know I have completly overwritten it instead of appending to it, because it was not set at all previously.)

I thought it worked, because when I run the terminal command java -XshowSettings:propertiesjava -XshowSettings:properties it returns this (among other things):

java.library.path = /opt/gurobi902/linux64/lib
        /usr/java/packages/lib
        /usr/lib/x86_64-linux-gnu/jni
        /lib/x86_64-linux-gnu
        /usr/lib/x86_64-linux-gnu
        /usr/lib/jni
        /lib
        /usr/lib

BUT when I want to load the library in my project with System.loadLibrary("GurobiJni90") I receive this exception:

Exception in thread "main" java.lang.UnsatisfiedLinkError: no GurobiJni90 in java.library.path: [/usr/java/packages/lib, /usr/lib64, /lib64, /lib, /usr/lib]

As you can see, the directory I've added previously is not listed in java.library.path of the exception statement.

Btw. this is my pom.xml entry for the library:

<dependency>
    <groupId>com.gurobi</groupId>
    <artifactId>gurobi</artifactId>
    <version>9.0.2</version>
    <scope>system</scope>
    <systemPath>/opt/gurobi902/linux64/lib/gurobi.jar</systemPath>
</dependency>

I think your issue is nothing to do with `LD_LIBRARY_PATH`, you even don't need setup this env variable. The `System.loadLibrary()` method rely on `java.library.path`, so you may need pass the `java -Djava.library.path=/opt/gurobi902/linux64/libGurobiJni90.so`. — Dai, Jul 14 '20 at 07:30
@Dai as described in https://www.gurobi.com/documentation/9.0/quickstart_linux/software_installation_guid.html it should work with setting the environment variable. Nevertheless I tried to use `java -Djava.library.path=/opt/gurobi902/linux64/lib` but nothing happens when I'm using that command. — Vega180, Jul 14 '20 at 08:22

score 1 · Answer 1 · answered Jul 14 '20 at 07:50

1

The environment variable LD_LIBRARY_PATH needs to point to a directory (or a list thereof), not to a specific library. This is also outlined in the Gurobi installation guide.

answered Jul 14 '20 at 07:50

mattmilten

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Yes, you're right. Thanks for pointing that out! Actually this was only a mistake I made when writing this question. I corrected it, the problem stays the same. – Vega180 Jul 14 '20 at 07:59

score 0 · Accepted Answer · answered Jul 14 '20 at 12:33

The issue is fixed now!

It seems like my linux distribution (Ubuntu 19.10) doesn't allow applications to read the .bashrc file where the environment variables are set. This explains why java.library.path hold different contents when accessed from the terminal or my own IntelliJ project.

The Gurobi Installation Guide mentions this issue (but I thought I wasn't affected):

In some Linux distributions, applications launched from the Linux desktop won't read .bashrc (or .cshrc). You may need to set the Gurobi environment variables in .bash_profile or .profile instead. Unfortunately, the details of where to set these variables vary widely among different Linux distributions. We suggest that you consult the documentation for your distribution if you run into trouble.

I've added the environment variables manually to my project in IntelliJ via the menu [Run] > [Edit Configurations] > [Environment variables] since I need them only in this project. Works for me!

UnsatisfiedLinkError on System.loadLibrary() after adding the directory to java.library.path

2 Answers2