How to fix an UnsatisfiedLinkError Can t find dependent libraries in a JNI project

Question

I m working on a Java project that uses the JNI   The JNI calls a custom library that I ve written myself  let s say mylib dll  and that depends on a 3rd party library  libsndfile-1 dll   When I run my program it crashes with   java lang UnsatisfiedLinkError   C     path    mylib dll  Can t find dependent libraries    I ve searched this site  and others  and I ve tried a number of fixes    I ran dependency walker  DW gave a couple of warnings -- that two libraries required by libsndfile  MPR DLL and SHLWAPI DLL  had  unresolved imports  -- but the DW FAQ said that these warnings could be safely ignored   I fixed the method names in mylib dll  as suggested here   The method names had somehow gotten mangled by the compiler  but I added linker flags and the dll method names now match those in my jni header file exactly  I put all of these DLLs in the same directory -- the same directory as the  jar that calls them -- to ensure that they re on the right PATH    No dice   Does anyone have any idea what s going on   I m doing my development in Visual Studio 2010 on a MacBook pro  via Parallels   I m doing my testing in Windows XP on a toshiba laptop

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In my situation  I was trying to run a java web service in Tomcat 7 via a connector in Eclipse   The app ran well when I deployed the war file to an instance of Tomcat 7 on my laptop   The app requires a jdbc type 2 driver for  IBM DB2 9 5    For some odd reason the connector in Eclispe could not see or use the paths in the IBM DB2 environment variables  to reach the dll files installed on my laptop as the jcc client   The error message either stated that it failed to find the db2jcct2 dll file or it failed to find the dependent libraries for that dll file   Ultimately  I deleted the connector and rebuilt it   Then it worked properly   I m adding this solution here as documentation  because I failed to find this specific solution anywhere else

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If you load a 32 bit version of your dll with a 64 bit JRE you could have this issue  This was my case

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When calling System loadLibrary    the JVM will look on the java library path for your native library  However  if that native library declares any dependencies on other native libraries  then the operating system will be tasked with finding those native library dependencies  Since the operating system has no concept of the java library path  it will not see any directories you place on the java library path  Instead  it will only search the directories on PATH environment variable of the operating system  This is totally fine if the native library dependency is an operating system native library because it will be found on the PATH  However  if the native library dependency is a native library that you or someone else created  then it will not be found on the PATH unless you place it there  This behavior is strange  unexpected  and not well documented  but it is documented in the OpenJDK issue tracker here  You can also find another StackOverflow answer reinforcing this explanation  here  So  you have a couple of options  You could either load each native library in the correct dependency order using System loadLibrary    or you could modify the PATH to include the directories where your native libraries are stored

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I m pretty sure the classpath and the shared library search path have little to do with each other   According to The JNI Book  which admittedly is old   on Windows if you do not use the java library path system property  the DLL needs to be in the current working directory or in a directory listed in the Windows PATH environment variable     Update   Looks like Oracle has removed the PDF from its website   I ve updated the link above to point to an instance of the PDF living at University of Texas - Arlington   Also  you can also read Oracle s HTML version of the JNI Specification   That lives in the Java 8 section of the Java website and so hopefully will be around for a while     Update 2   At least in Java 8  I haven t checked earlier versions  you can do   java -XshowSettings properties -version   to find the shared library search path   Look for the value of the java library path property in that output

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I found a great article by some friends at keepsafe that went through the same thing I did  It worked for me  so hopefully it helps you out as well  Have a read if you re interested  The Perils of Loading Native Libraries on Android  or just use   compile  com getkeepsafe relinker relinker 1 2 3   and replace   System loadLibrary  myLibrary      with   ReLinker loadLibrary context   mylibrary

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installing Microsoft Visual C   2010 SP1 Redistributable Fixed it

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place the required dlls in folder and set the folder path in PATH environment variable  make sure updated environment PATH variable is reflected

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Did have identical problem with on XP machine when installing javacv and opencv in combination with Eclipse  It turned out that I was missing the following files    msvcp100 dll msvcr100 dll   Once these were installed  the project compiled and ran OK

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Short answer  for  can t find dependent library  error  check your  PATH  corresponds to bullet point  3 below  Long answer    Pure java world  jvm uses  Classpath  to find class files JNI world  java native boundary   jvm uses  java library path   which defaults to  PATH  to find dlls pure native world  native code uses  PATH to load other dlls

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You need to load your JNI library   System loadLibrary loads the DLL from the JVM path  JDK bin path    If you want to load an explicit file with a path  use System load    See also  Difference between System load   and System loadLibrary in Java

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Go to http   tess4j sourceforge net usage html and click on Visual C   Redistributable for VS2012 Download it and run VSU 4 vcredist x64 exe or VSU 4 vcredist x84 exe depending upon your system configuration Put your dll files inside the lib folder  along with your other libraries  eg  lib win32-x86 your dll files

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I was facing same issue with ffmpeg library after merging two Android projects as one project      Actually issue was arriving due to two different versions of ffmpeg library but they were loaded with same names in memory  One library was placed in JNiLibs while other was inside another library used as module  I was not able to modify the code of module as it was readonly so I renamed the one used in my own code to ffmpegCamera and loaded it in memory with same name    System loadLibrary  ffmpegCamera      This resolved the issue and now both versions of libraries are loading well as separate name and process id in memory

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I used to have exactly the same problem  and finally it was solved    I put all the dependent DLLs into the same folder where mylib dll was stored and make sure the JAVA Compiler could find it  if there is no mylib dll in the compilation path  there would be an error reporting this during compiling   The important thing you need to notice is you must make sure all the dependent libs are of the same version with mylib dll  for example if your mylib dll is release version then you should also put the release version of all its dependent libs there    Hope this could help others who have encountered the same problem

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I want to inform this interesting case  after tried all the above method  the error is still there  The weird thing is it works on a Windows 7 computer  but on Windows XP it is not  Then I use dependency walker and found on the Windows XP there is no VC   Runtime as my dll requirement  After installing VC   Runtime package here it works like a charm  The thing that disturbed me is it keeps telling Can t find dependent libraries  while intuitively the JNI dependent dll is there  however it finally turns out the JNI dependent dll requires another dependent dl  I hope this helps

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Please verify your library path is right or not  Of course  you can use following code to check your library path path  System out println System getProperty  java library path      You can appoint the java library path when launching a Java application   java -Djava library path path

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Creating static library worked for me  compiling using g   -static  It bundles the dependent libraries along with the build

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I had the same issue  and I tried everything what is posted here to fix it but none worked for me  In my case I m using Cygwin to compile the dll  It seems that JVM tries to find the JRE DLLs in the virtual Cygwin path  I added the the Cygwin s virtual directory path to JRE s DLLs and it works now  I did something like       SET PATH   cygdrive c Program Files Java jdk1 8 0 45   PATH

[java] How to fix an UnsatisfiedLinkError (Can't find dependent libraries) in a JNI project

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