I am having an issue when loading a dll file using java. I am getting
java.lang.UnsatisfiedLinkError: Unable to load library 'C:\Users\GZammit\Documents\gapt\RwLibraries': Native library (win32-x86-64/C:\Users\GZammit\Documents\gapt\RwLibraries.dll) not found in resource path ...
This is my code :
ClassApi INSTANCE = (ClassApi) Native.loadLibrary(System.getProperty("user.dir")+"\\RwLibraries\\renderwarriors", ClassApi.class);
I did a lot of research and I know there are many with same error but none of the solutions worked for me. The weird thing is, it shows you which files it searched and one of the files is the actual path of the dll location. I even printed out both urls to confirm. I also placed the dll in many other location including the sysWOW64.
I also changed the java.library.path before loading the dll to make sure it is in that particular path without success either. I also followed multiple tutorials online doing exactly the same code without success.
I am using jna 4.4.0 jar file and jna-platform 4.4.0 . I checked the java path and also placed a dll in one of the paths mentioned.
There should be no error code-wise since it worked for my team but not on my computer. I also tried on two different computers.
Everything is 64-bit including the dll.
Related
I am trying to run a program which uses JMagick. I have added the native library libJMagick.so as well as libMagick.so.10 (64 bit, matching my system's architecture) to my java.library.path. But when I am trying to run the program I am getting following error:
libJMagick.so: libMagick.so.10: cannot open shared object file: No
such file or directory
From error, it looks like it is finding the libJMagick.so file, but it is not able to find libMagick.so.10, although it is present in java.library.path.
I have ImageMagick installed in my system.
When you copy the .so files, Please do it in respective folders. So that the Java application will load the libraries available for the usage. This is all about your configuration issue. Where to store the shared object files, They should be available on the path.
I am working on a Java project in NetBeans using JNA. According to the JNA documentation, I can make my DLL:s available to Java by putting it in the jar:
Make your native library available on your classpath, under the path {OS}-{ARCH}/{LIBRARY}, where {OS}-{ARCH} is JNA's canonical prefix for native libraries (e.g. win32-x86, linux-amd64, or darwin). If the resource is within a jar file it will be automatically extracted when loaded.
This is what I want to do, so I have included the DLL:s in the project under src/win32-x86-64. If I build a jar-file with netbeans, and then include the jar file in another project everything works fine and JNA finds my library without a problem. This is what I get with jna.debug_load on:
Looking in classpath from sun.misc.Launcher$AppClassLoader#15db9742 for /com/sun/jna/win32-x86-64/jnidispatch.dll
Found library resource at jar:file:/C:/MyNetBeansProject/dist/lib/jna-4.2.2.jar!/com/sun/jna/win32-x86-64/jnidispatch.dll
Looking for library 'MyLibrary'
Adding paths from jna.library.path: null
Trying MyLibrary.dll
Adding system paths: []
Trying MyLibrary.dll
Looking for lib- prefix
Trying libMyLibrary.dll
Looking in classpath from sun.misc.Launcher$AppClassLoader#15db9742 for MyLibrary
Found library resource at file:/C:/MyNetBeansProject/build/classes/win32-x86-64/MyLibrary.dll
Looking in C:/MyNetBeansProject/build\classes\win32-x86-64\MyLibrary.dll
Found library 'MyLibrary' at C:/MyNetBeansProject/build\classes\win32-x86-64\MyLibrary.dll
Apparently the DLL from the jar is not used. Instead the DLL from the build folder is used.
Now, if I move the jar-file to another folder and include it in my project, I get a UnsatisfiedLinkError. JNA gives the following output:
Looking in classpath from sun.misc.Launcher$AppClassLoader#70dea4e for /com/sun/jna/win32-x86-64/jnidispatch.dll
Found library resource at jar:file:/C:/SomeFolder/lib/jna-4.2.2.jar!/com/sun/jna/win32-x86-64/jnidispatch.dll
Looking for library 'MyLibrary'
Adding paths from jna.library.path: null
Trying MyLibrary.dll
Adding system paths: []
Trying MyLibrary.dll
Looking for lib- prefix
Trying libMyLibrary.dll
Looking in classpath from sun.misc.Launcher$AppClassLoader#70dea4e for MyLibrary
Found library resource at jar:file:/C:/SomeFolder/MyNetBeansProject.jar!/win32-x86-64/MyLibrary.dll
It looks like JNA finds the DLL in the jar, but it does not try to extract it. I can not find it in my temp folder (where JNA extracts it's own internal DLL).
What is the problem here? Why doesn't JNA extract the file? How can I fix this?
(I don't know if this is relevant, but I should mention that my DLL depends on multiple other DLL files that are in the same folder in the jar. Not sure if JNA will extract them automatically for me, but so far it seems JNA isn't even extracting the DLL I am actually using.)
EDIT: There seems to be no problem locating jnidispatch.dll. According to the output when jna.debug_load.jna is set to true the file is found in the JAR and extracted to the temp folder.
JNA show error "UnsatisfiedLinkError" when dll couldn't be loaded. If your DLL needs another custom DLLs not present in the system path it will fail, as JNA doesn't extract this dll automatically.
JNA as a Java library doesn't know the dependencies of the system library, so it can't extract from the jar. The solution is to specify all the dependencies in the JNA Java interfaces.
You can see an example here Load multiple dependent libraries with JNA
What is happening behind the scenes of the Operating System
At the end, the libraries are loaded by the operating system as requested by the main executable. In this case the main executable is java.exe or (jvm.dll). If the system can't find a library in the path it fails and java generates an exception.
Another related and solved question is Registering multiple .dll libraries into a single java class using JNA
I am trying to implement a wrapper for native libraries that will be consumed via JNI in a Java application. I want to make installation of the program be as simple as "Unzip this file and run".
I've worked through most of the wrapper so far, getting it to unzip the native libraries from inside the platform-specific JAR file and setting the -Djava.native.lib variable at runtime. I've hit one last roadblock due to unsatisfied link errors.
On Windows, the DLLs that I'm calling link against msvcr100.dll. While the DLLs that I'm calling into are getting picked up by java.native.lib, msvcr100.dll isn't. I don't want to have to require the user to install the C++ runtime before using our app, so we are packaging the DLL file right along side the other DLLs.
As far as I understand, to get things to work we need to put the folder that contains msvcr100.dll on the PATH. I tried using reflection to change the environment inside the application to add the unpack directory to the PATH environmental variable. After this was unsuccessful, I recalled that I was only modifying a copy of the environment.
Is there some way that I can fix the unsatisfied link error without requiring any additional system setup (installing the runtime, hand modification of PATH, etc)? I would think it is possible since I've encountered other pieces of software (SWT, JOGL) that package native libraries that don't exhibit this issue.
Hi I am trying to run a project in eclipse and am getting the runtime error:
Exception in thread "main" java.lang.UnsatisfiedLinkError: mywrapperclass.nativemethod()V
I only get the error code when I call a native method in the wrapper class from my main. I have looked around on many forums and blogs/websites and haven't been able to fix this. Debug and my browsing have me led me to thinking that the problem lies in the project not being able to find the native methods within the dll.
I had a lot of trouble getting eclipse to find the .dll and eventually solved this by placing the dll in the system32 folder.
Thanks in advance
Project > Properties > Java Build Path
Click on the arrow of the JAR that needs the DLL library.
Native library location
You have to specify the location of the DLL library.
Easiest way to bundle the dlls with eclipse plugin is
create a folder structure under the plugin like this "os/win32/x86" for x86 architecture and place your dlls there.
and load the libraries like this in your plugin code System.loadLibrary("Dll name");
open .classpath in the project location
Set the dll path as "value" for "CLASSPATH_ATTR_LIBRARY_PATH_ENTRY" attribute
I'm writing some JNI code in C++ to be called from an applet on Windows XP. I've been able to successfully run the applet and have the JNI library loaded and called, even going so far as having it call functions in other DLLs. I got this working by setting up the PATH system environment variable to include the directory all of my DLLs are in.
So, the problem, is that I add another call that uses a new external DLL, and suddenly when loading the library, an UnsatisfiedLinkError is thrown. The message is: 'The specified procedure could not be found'. This doesn't seem to be a problem with a missing dependent DLL, because I can remove a dependent DLL and get a different message about dependent DLL missing. From what I've been able to find online, it appears that this message means that a native Java function implementation is missing from the DLL, but it's odd that it works fine without this extra bit of code.
Does anyone know what might be causing this? What kinds of things can give a 'The specified procedure could not be found' messages for an UnsatisifedLinkError?
I figured out the problem. This was a doozy. The message "The specified procedure could not be found" for UnsatisfiedLinkError indicates that a function in the root dll or in a dependent dll could not be found. The most likely cause of this in a JNI situation is that the native JNI function is not exported correctly. But this can apparently happen if a dependent DLL is loaded and that DLL is missing a function required by its parent.
By way of example, we have a library named input.dll. The DLL search order is to always look in the application directory first and the PATH directories last. In the past, we always ran executables from the same directory as input.dll. However, there is another input.dll in the windows system directory (which is in the middle of the DLL search order). So when running this from a java applet, if I include the code described above in the applet, which causes input.dll to be loaded, it loads the input.dll from the system directory. Because our code is expecting certain functions in input.dll which aren't there (because it's a different DLL) the load fails with an error message about missing procedures. Not because the JNI functions are exported wrong, but because the wrong dependent DLL was loaded and it didn't have the expected functions in it.
There is a chance that the DLL was built using C++(as opposed to C). unless you took care to do an extern on the procedure,this is one possible reason.
Try exporting all the functions from the DLL. If the list includes your function, then you're good.
Usually, when linking to other libraries, you need to link to the relevant .lib file. It sounds like you aren't referencing all the lib files you need. Check what isn't linking and make sure you add it's lib to the list for the linker.
Did you create the new external DLL using the standard JNI procedure? I.e., using javah and so forth? If so, then I am not sure what is wrong.
If not, then the procedure you're trying to call hasn't been exported (as mentioned by anjanb). I am aware of two way of exporting functions: a separate export list and marking specific functions with __declspec(dllexport).
Can't access variable in C++ DLL from a C app has a little more information the topic of DLLs.
Compile your c++ code in debug mode. Then insert the DebugBreak(); statement where you would like to start debugging. Run the java code. When the DebugBreak() statement is encountered you will get a popup with a Debug button on it. Click on it. Dev Studio will open with your program in machine code. Step over with the debugger twice and you should be able to step over your source code.
If you have done all programming issue at JNI manuals and examples but still you are getting same missing procedure error, problem can be at your path variable probably. Do below steps and run again:
Be sure about you set JAVA_HOME variable to your JDK folder(not JRE because JRE doesnt contain jni header)
Example:
At environment variable settings panel define var:JAVA_HOME val:C:\Program Files\Java\jdk1.7.0_11
add %JAVA_HOME%\bin to your path variable
After doing those steps, your application can find jni procedure name and links to JNI.dll in right way. So, i hope you dont get this missing procedure error again.