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)
The Problem
Currently I use exe4j 4.4.2 to wrap our client app in a Windows native executable, but the result does not integrate with Windows 7 so well.
For example: When I right click in the task bar it only offers a pop-up to close the application but no pinning. Eclipse' Equinox launcher on the other hand does that with bravado.
I'm looking for a java exe launcher which has the following features:
Wraps jars in Windows native executables (no Java Web Start or similar)
Doesn't extract the jar from the executable
Doesn't need write access in "Program Files"
Uses executable filename as process name (only one process)
Integrates well with Windows 7 (esp. pinning in the taskbar)
Allows setting of JVM arguments (esp. heap size)
Flexible customization for JRE search
Lightweight
Actively maintained
Integrates well in Ant build
Preferably free
I have checked the following:
exe4j
Windows 7 integration lacking
It's not expensive but ordering and
distribution of licenses to the build machines is a pain.
JRE search not flexible enough
Eclipse Equinox
Not lightweight
Seems to do everything I want, except that I have no idea how
to use it with a non-eclipse-based app.
Can I use it outside of OSGI, PDE-Build world?
WinRun4J
JRE search not well documented
Seems not widely used despite incredible feature set, what am I missing?
Launch4J
Doesn't support setting the process name in Windows 7 (Bug ID 3353972).
There is a patch (Bug ID 1670471) but it has been rejected with reference
to jliftoff which is dead.
JRE search not flexible enough.
JSmooth
Seems not to be actively maintained.
Latest release is from 2007, well before Windows 7.
Are there any other options?
Is there a chance to use the Eclipse launcher with a non Eclipse-base application?
Try Advanced Installer http://www.advancedinstaller.com/java.html (There is a free edition available in this).
I'm happy with WinRun4J. The JRE search works fine for me. It sometimes chokes especially on 64bit systems if multiple JREs and JDKs are installed and registered in the Windows registry, but this can usually be fixed by supplying the correct path in the corresponding .ini file.
I did not use Launch4J because it creates a new (temporary) .exe in the JRE installation folder which seems a bit strange to me. The advantage of that method is, that it can use a single .exe for both 32 and 64 bit JVMs though
It sounds to me like you just need to go with Launch4J. The process name matches the .exe name that you launch with. A great example of a program that is wrapped this way is "Keystore Explorer 4.01".
I would create a bat file. Wrap this bat file into a exe. You can create an exe with an icon and everything. Try this bat to exe converter:
http://download.cnet.com/Bat-To-Exe-Converter/3000-2069_4-10555897.html
In this way, you have better control. The size of the exe is very small.
Edit: Also, the creation of the exe is one time thing.
I make my executable jar in exe format, but I want to add JRE with this because if JRE is not present in their machine, they can use it with this included JRE.
But I do not want to install this JRE in their machine. This JRE is only used by this application only. It will just like game or other application. I use launch4j to make jar to exe but i did not find any option from where it can attach JRE and it has no option from where I can link my jar dynamically.
How do I achieve that?
If there is other free installer then mention it, and please give the procedure with example.
Since it has been established that your app. has a GUI, I will suggest Java Web Start as the answer.
But I do not want to install this JRE in their machine.
That is not a sensible requirement. The user might already have a usable JRE installed, if they don't they probably also don't want every Java based application to be installing its own 'private' JRE.
Oracle's deployJava.js can do the checking, and help guide the user through the steps of installing (which basically comes down to click 'OK' when prompted).
I make my executable jar in exe format,..
If you only intend to support Windows, what is the attraction of coding in Java? JWS supports any platform for which Java is available. That brings a lot more potential customers for the app.
I want to use free installer.
JWS is entirely free. Just like the JRE.
..please give the procedure with example.
Do you run an IDE? If not, do you otherwise have Ant installed? If that is a yes to either one, check out my small JNLP API examples. Each comes with complete source and a build file (an Ant build.xml).
Within a couple of keystrokes & a few moments, you can see the app. installed and launched on your desktop. For the end user, it is even simpler. Just click a link in a web page, and it all happens automatically (possibly with a security prompt - for the protection of the user).
I like JSmooth. You can give it a try here:
http://jsmooth.sourceforge.net/features.php
Flexible automatic Java VM detection
Detects the location of any Sun JVM installed. The wrappers use
several strategies to detect all the JVM available on a computer,
using windows registry, environment variables, windows path.
Detects
and uses Microsoft's JView (for 1.0 and 1.1 Java applications), if
available.
The JVM search sequence is fully customizable using the
GUI. You can force the executable to search in the path first, and in
the registry last, or in JAVA_HOME first. We have all the flavours!
Sometimes it's more convenient to bundle a JRE with your application.
JSmooth can deal with that too, you just need to define in which
folder the JRE is expected. It falls back nicely to a standard JVM
search if the JRE is not where it should be.
Specify which versions of
the JVM are compatible with your software. You can set a minimum
version, but also a maximum JVM version.
Documentation: http://jsmooth.sourceforge.net/docs/jsmooth-doc.html
Take a look at launch4j.
I had to use it, and it worked out very well.
You can set a minimum version of a needed JRE, bundle a JRE, or if a JRE is not found (and not bundled) the launcher may lead the user to a download location of an appropriate JRE.
There are various further features launch4j offers, and as opposed to another suggestion here, launch4j is activly developed
http://launch4j.sourceforge.net/
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 have created an exe with a launch4j Ant script and build.xml file. I want to bundle the JRE in my application and have to distribute it to clients. How do I do this?
Thanks,
Rajani
Well, just bundle everything under $JAVA_HOME/jre into your distribution (presumably a Zip/TAR file) and then have your scripts reference that (i.e. use the java executable under $JRE_HOME/bin to run your java program).
Remember that if you do this, you will have to deliver different distributions for different target platforms (Windows,OSX, linux etc) and architectures (or one bloated uber-distribution of course, but no one will thank you for that!).
This works great... if you want your program to run on just a single version of a specific OS.
Generally, though, bundling a JRE is a bad idea. Even on Windows, there are three versions of the JRE: one for x86, one for x86-64, and one for Itanium. Even if Sun does make it hard to find the 64-bit versions, they still exist.
The 64-bit versions of Java for Windows are actually on java.sun.com, but not java.com.