I'm trying to use the C++ library Spot (https://gitlab.lrde.epita.fr/spot/spot) in a Java project. I wanted to realize the interface between Java and C++ with JNA (https://github.com/java-native-access/jna). Because the Java application should also run on Windows, I tried to cross compile the library first with
./configure --host=x86_64-w64-mingw32 --disable-python LDFLAGS="-static -static-libstdc++ -static-libgcc"
and then of course make/make install on a Linux system. Because I can't expect the Windows system to have libstdc++/libgcc I wanted to link it statically into the library. My problem is now the following: When I try to open an compiled .exe in Windows, it still tells me libstdc++/libgcc not found. Of course, JNA also gives me an UnsatisfiedLinkException when I try to load the library in my Java program, because the modules are still not found, even though i explicitly linked them statically.
So what am I doing wrong? What else can I try to avoid having libstdc++/libgcc installed on the host system? I am now trying this for a week and have no clue how to overcome this, so a question here is kind of my last resort.
Thanks
I'm currently working on a home-project and I had to use GLPK. I'm working on Eclipse and Windows.
So I've set the java build path properly in my project, did my stuff, everything was working fine, and one day I had some surprise java update, which screwed everything. Now I'm having this message :
The dynamic link library for GLPK for Java could not be loaded.
Consider using
java -Djava.library.path=
The current value of system property java.library.path is:
C:\Users\Marks\workspace\TER\librairies\jdom;C:\Users\Marks\workspace\TER\librairies\glpk-4.55\w64
And I can't achieve to make my project work again, I've tried everything, loading the DLL with System.load, building with an older GLPK version, trying to compile by myself the glpk.
From the given information it seems everything is setup correctly.
I once had a similar error after a java update where it messed up the 32 bit and 64 bit Versions on my machine (setting 32 bit as default). So the execution of the Source on 32 bit Java requires the dynamic link libraries located in the glpk-4.55\w32 directory.
I'm attempting to run the Java version of OpenCV on a hosted Ubuntu server. I have an existing application built using Eclipse from my own windows environment and i want to move it over to my server to run it there. However i am having several issues with it.
The problem is that when i try to run it i receive the following error:
Now there are existing question with varying answer to this problem already on SO, the problem being the UnsatisfiedLinkError, but i have tried to follow them to no avail.
I have eclipse pointing the native library location to where opencv is located on the server itself as so;
But i still have the same problem. I am compiling this project as a Runnable Jar File if that makes any difference.
The paths must match (between Windows and Linux) and you must have the right native file for each system included (and tested for).
Currently in your Eclipse environment you are pointing to a Windows implementation of OpenCV - how will Linux know where to look?
I would make sure Eclipse includes all libraries when creating a runnable jar file (it is a checkable option), and make sure that your .dll and .so files all go into the same location regardless of system (so make sure the opencv dll is in c:\var\lib\opencv and libopencv_java249 is in /var/lib/opencv on the linux box)
In your program, since versions may not be the same, when loading the library in - do it this way too:
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
That way it will use whatever version is current on your system.
I am trying to use the thinkgear.dll library to connect with a NeuroSky Mindset.
The developer tools include a ThinkGear.java class, which is a wrapper around the thinkgear.dll. The dll is only 32 bit compatible. I get a Can't load IA 32-bit .dll on a AMD 64-bit platform error when trying to run the program. This is only going to be run on my computer, not distributed. I've read that I have to run the jre in 32 bit mode or something?
Also, I am not sure I have set up the library to reference it properly. How should I do that, starting with a brand new project, where should I put the dll and thinkgear.java to be able to use the methods in my NeuroSkyApp class? Sorry, I am very new to java, I don't really understand all of this yet.
Here is a screenshot of what I have in Eclipse:
You need to install a 32-bit JRE and configure the build environment for your project in Eclipse accordingly.
To add an external dll to your project, you might find useful information here: How to add native library to "java.library.path" with Eclipse launch (instead of overriding it)
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).