CODEWITHSUNDEEP
java
Steven Jeffries
Steven Jeffries

Reputation: 3572

What is java.library.path set to by default?

I'm just wondering how, exactly, does Java go about deciding the default value for its java.library.path property?

I am running a *buntu 14.04 64 bit, and it defaults to (the first two don't exist):

/usr/java/packages/lib/amd64
/usr/lib64
/lib64
/lib
/usr/lib

Searching through my environmental variables, I have found that nothing has these in it. Setting LD_LIBRARY_PATH does prepend its contents to this list.

Given this information, I am assuming that this list is just explicitly set (hard-coded) into Java, but I can't find any documentation on it. Is my assumption correct? What are its default values for different OSs? Will these values change across distributions?

I'm asking for two reasons. 1) I'm just curious. 2) I want to know where I can put a library so that Java will always find it.

Upvotes: 6

Views: 10682

Answers (2)

Thorgull
Thorgull

Reputation: 41

On my Debian system, if I check the value of java.library.path with the command 

java -XshowSettings:properties

The java from the system package installed return the correct value : 

/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

The java from the open-jdk I downloaded on openjdk site returns :

/usr/java/packages/lib
/usr/lib64
/lib64
/lib
/usr/lib

I found each returned value in the binary libjvm.so of the corresponding jdk/jvm

Upvotes: 4

DesirePRG
DesirePRG

Reputation: 6378

If you want to find the path which is set currently in your machine, run the following.

System.out.println(System.getProperty("java.library.path"));

you can explicitly set the path in your code as following

System.setProperty(“java.library.path”, “/path/to/library”);

through command line

java -Djava.library.path=<path>

Also I wouldn't call it an environment variable. It is a system property used by the jvm.

Upvotes: -2

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