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After doing some research, some people say I can add the following VM Argument in my project Run Configuration. In run time, JVM will search these directories to find DDLs.

-Djava.library.path="${workspace_loc}/GunCalibration/myLib/DLLs;${env_var:PATH}"

GunCalibration is my Java project folder in my workspace. DLLs folder contains all my DLLs which are defined with my JNI specification.

As a result, I get this error:

Exception in thread "main" java.lang.UnsatisfiedLinkError: D:\Software x64\eclipse3.7\Kai\workspace_RealW\GunCalibration\myLib\DLLs\sixense.dll: Can't find dependent libraries

However, if I copy some specific dll files to JAVA_HOME\jre6\bin, my code works correctly. (I do add this path into my system environment PATH.)

Could anyone explain why the first approach by using java.library.path doesn't work? How can I know which ddl is required to place in JAVA_HOME\jre6\bin?

Thank you a lot~

technomage
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enix0907
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  • Any chance there's some 32/64-bit issues? – nitind May 31 '12 at 05:01
  • @technomage I try to add my path **D:\Software x64\eclipse3.7\Kai\workspace_RealW\GunCalibration\myLib\DLLs** where my DLLs store to PATH environment variable, but it still shows me the same error. So these DLLs can only be found in JAVA_HOME\jre6\bin ? Thanks again. – enix0907 Jun 01 '12 at 03:28
  • Use dependency walker (http://dependencywalker.com) to determine the full list of DLLs you require, then make sure the paths to *all* of them are included in your PATH. – technomage Jul 09 '12 at 15:59

1 Answers1

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JAVA_HOME\jre6\bin is effectively in the system PATH (since it's the same directory as the java.exe program which is being run), which makes any DLLs there loadable by the system. java.library.path is mostly derived from the value of PATH, but it only affects where the VM looks for native libraries, not the system itself.

The VM can load any file explicitly based on the paths in java.library.path, but it cannot affect how the system looks up any dependent DLLs (other than telling the system to include the path to the initial DLL in its search -- see MSDN for LoadLibrary[Ex])

One alternative to copying the DLLs is to add the path to the DLLs to the PATH environment variable.

technomage
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