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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.
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.
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.
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
If you load a 32 bit version of your dll with a 64 bit JRE you could have this issue. This was my case.
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 ...
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.
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.
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
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");
installing Microsoft Visual C++ 2010 SP1 Redistributable Fixed it
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.
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%
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.
Creating static library worked for me, compiling using g++ -static. It bundles the dependent libraries along with the build.
place the required dlls in folder and set the folder path in PATH environment variable.
make sure updated environment PATH variable is reflected.
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.
I faced the same problem after migrating my CI into a new machine.
I was still facing it even after applying all the above solutions.
The problem was in my new machine, there was Microsoft Visual C++ 2010 SP1 Redistributable x86 installed in it. But my new machine was having 64-bit CPU and operating system. So the fix was that i just updated and installed the 64 bit version from here .
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).
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.
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.
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.
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
If you load a 32 bit version of your dll with a 64 bit JRE you could have this issue. This was my case.
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 ...
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.
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.
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
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");
installing Microsoft Visual C++ 2010 SP1 Redistributable Fixed it
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.
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%
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.
Creating static library worked for me, compiling using g++ -static. It bundles the dependent libraries along with the build.
place the required dlls in folder and set the folder path in PATH environment variable.
make sure updated environment PATH variable is reflected.
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.
I faced the same problem after migrating my CI into a new machine.
I was still facing it even after applying all the above solutions.
The problem was in my new machine, there was Microsoft Visual C++ 2010 SP1 Redistributable x86 installed in it. But my new machine was having 64-bit CPU and operating system. So the fix was that i just updated and installed the 64 bit version from here .
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).
I am developing a java application where i require image conversion and I want to use imageMagick for that.
I made a java program using jmagick.jar in classpath and then installed imageMagick. Then the program was running as expected. But i want to pack imageMagick component in my application, so separate installation should not be done.
So i copied the program files from original place to somewhere else and uninstall imageMagick. Then Ii gave JVM argument as -Djava.library.path="F:\\ImageMagick-6.3.9-Q16\\"
So i am getting error as Exception in thread "main":
java.lang.UnsatisfiedLinkError: F:\ImageMagick-6.3.9-Q16\jmagick.dll: Can't find dependent libraries
So please tell me how and where to give dependent libraries path in program and how to use imageMagick without installing. I tried searching through web. but didn't get any useful information
Rather then coping dll files around, use something like Maven to manage your dependencies. Your project now has a dependency of jmagick; which in turn, has a prequisite of ImageMagick (see section 0 in JMagick INSTALL document.)
How to use ImageMagick without installing
You can not. The system running your application will need to have Imagemagick libraries, headers, and delegates to satisfy JMagick.
Ideally your project should included a installation script that checks for system dependencies, and respects environment variables that may be defined by a system administrator. See ImageMagick hints for details that can influence installation.
I'm running a big application and a small part of it includes Java 3D, the problem is many users need to use the code, but it isn't practical for everyone to install Java 3D just to run the application if they aren't even going to use that section of the application.
Is it possible through compiling an extra jar, or changing some paths, to include Java 3D in a project without installing it on a system? Or perhaps to manually include any dlls?
The demos at java3d prove that it is possible.
You only need to include the required jar files to your projects distribution.
Yes, it is possible. You will need to pull the required jars and native libraries from the java3d site. I pulled them from the java3d demos, but that requires digging through the xml launch descriptor files.
The place you'll run into the most trouble is when linking to the .so / .dll files. This is typically specified on the classpath before your app starts, but since you don't know what platform you're using until your app starts, it's a catch22.
There are two possible solutions:
1. Bootstrap your program with a simple class that detects the platform and sets up a new jvm (with the proper libraries specified) for the real application.
2. Dynamically load the libraries (I've never actually used this method for native implementations, but I see no reason why it wouldn't be possible).
Unfortunately, neither method is terribly straight forward.
I've done this with no problems (and many users tested that it works, Windows OS) by simply adding the jars to the classpath and dropping the appropriate dlls into the "working" directory where the .bat file running Java started. One catch is I had to have two bat files - one 32 bit and one 64 bit. Each bat file copy/renames the appropriate dll to j3dcore-ogl.dll, since depending on which version of Java (32/64 bit) you're running, a different jar is needed.
Example .bat file:
del j3dcore-ogl.dll
copy j3dcore-ogl-64.dll j3dcore-ogl.dll
java -Xmx2048m -classpath ./YourJar.jar;./lib/tinylaf.jar;./lib/j3dcore.jar;./lib/j3dutils.jar;./lib/vecmath.jar your.package.MainClass
#pause
I made a simple java program that sends bytes to the parallel port, which uses a .dll along with two other classes (pPort.java and ioPort.java) to accomplish it, and it works perfectly fine.
However, I started making another program on NetBeans IDE which has a similar function. It compiles perfectly, but when I run it I get:
Exception in thread "AWT-EventQueue-0" java.lang.UnsatisfiedLinkError: parallelporttimer.ioPort.Out32(SS)V
From what I understand, it's failing to call the .dll file I put on System32. But I don't understand why, since the other program, which is basically the same but made manually without any IDE, runs fine. Do I have to specify something in NetBeans for this to work? Any help with this would be greatly appreciated.
DLL needs to be in the path or current working directory in order to be loaded.
I'm guessing when you've ran your program without IDE the latter was the case. When you run it from within NetBeans "working" directory is likely netbeans/bin folder, so DLL can't be found. Add its location to path and you should be good to go.
I don't do Netbeans, but it sounds like that Netbeans maintains its own java.library.path. Best what you could try is to specify it yourself as VM argument:
-Djava.library.path="c:/path/to/dll/files"
An UnsatisfiedLinkError message typically indicates that the library path is set but does not include the library that you are trying to load. On Windows platforms, you should extend the PATH using
PATH = %PATH%;C:\path_to_dll_file
On UNIX platforms, you should extend the library path using
setenv LD_LIBRARY_PATH mylibrarypath
However, as far as I can remember (I'm not under Windows), System32 is in the PATH so I suspect NetBeans to overwrite it by settings its own PATH.
To solve this on NetBeans, you might want to check http://wiki.netbeans.org/DevFaqNativeLibraries which is mentioned in this message from Wade Chandler, a NetBeans Dream Team Member ;-)
PS: You can also use the java.library.path system property but keep in mind that this system property only works to resolve the immediate native library that you are loading in your code. Loading of other dependent libraries is left to the first library. The JNI library that you load will rely on the OS dependent way to resolve its references (this applies to the solution of the FAQ too IMO so I'm still not 100% convinced its a good solution).
Have you looked into the two classpaths for both programs (standalone and IDE) ?
In my case the cause was not the missing library, but the use of 64 bit Java JDK as default java platform for Netbeans.
(It did not help to add the "-d32" flag.)
The problem was solved by:
Adding a 32 bit java platform to Netbeans (Menu: Tools/Java platforms) and
Assigning it as the platform for the project (Project properties/Libraries/Java Platform).