Develop Reference

Native library bluecove not available on Mac

I downloaded bluecove-2.1.0.jar and added it as an external JAR on my Eclipse project. I am following this tutorial for using Bluetooth with Android: http://luugiathuy.com/2011/02/android-java-bluetooth/
When I run the program intended for my laptop to act as a server, I get an error stating 'Native library bluecove not available'. I made sure bluetooth was enabled by typing 'bluetooth' in Spotlight (which took me to Bluetooth File Exchange and allowed me to select a file to send).
I saw another Stackoverflow post stating that BlueCove requires 32-bit JVM to run so I added the -d32 argument under VM arguments in the run configuration. When I ran it, I got another error stating
"Error: This Java instance does not support a 32-bit JVM.
Please install the desired version."
Does anyone have any ideas on how to fix this?

Try using OpenJDK rather than the Oracle JDK. This supports the -d32 arguments so it ought to work for you.

OpenJDK may work as Mike suggested but its installation process was rather involved. I found a workaround by installing an earlier version of Eclipse that supported 32-bit OS X versions and setting -d32 in the VM arguments there worked without issues. Be sure to keep the earlier version of Eclipse in a separate folder so it doesn't overwrite your recent version.
I installed the 32-bit version of Eclipse Kepler from here: https://eclipse.org/downloads/packages/release/Kepler/SR2
Of course, Bluecove had some other issues with IOBluetooth device not found (since Apple removed that since OS X 10.8 I believe), for which you can check here for a possible solution.

Architecture Missmatch

I'm trying to run a java program that links to an Access database in netbeans. I am aware that Access is 32bit and the JDK is 64bit. I created the link using %WINDIR%\SYSWOW64\ODBCAD32.exe.
Now, I'm getting this error: Architecture mismatch. What do I have to install to be able to run this program? I have tried to find a solution on here, but I just don't understand the exact steps I need to follow.

You will need 64-bit drivers as your Java app is running 64-bit. I believe there is a 64-bit download at the below link:
http://www.microsoft.com/en-us/download/details.aspx?id=13255

Java 7 and JavaVM.framework on mac

I played with Java 7 update 9 on mac a little bit and found an interesting thing.
I just ran a simple Java program with a JFrame, and attach to it with lldb. Then I checked libraries loaded by this Java program and I saw:
"/System/Library/Frameworks/JavaVM.framework/JavaVM" in it.
So i have 2 questions:
what does this JavaVM do for Java 7? I thought Java 7 on mac is self-consistent like its corresponding versions on Windows and Linux. By using "nm", I can see this JavaVM defined many functions like JNI_CreateJavaVM, which is also defined in libjvm.dylib.
what should I link to for JNI libraries with Java 7? still JavaVM.framework? Can I link to libraries located under
/Library/Java/JavaVirualMachine/jdk.1.7.0 directly.
Any help will be much appreciated.

For the first part, that JavaVM points to the Mac JavaVM (1.6). Taking a closer look at the Info.plist files, it looks like the Mac Java supports JNI (amongst other things), while the Oracle Java supports only CommandLine. It does not look like you can link to 1.7 on Mac OS X. There's plenty of related questions, too.
To find your JVMs that support JNI, do this:
/usr/libexec/java_home -t JNI
This should probably return the 1.6.0 JDK. You can run it with the -V argument to get a full listing of what JVMs are available.

The Oracle JDK on Mac is advertised to be just like the Oracle JDK everywhere else. It's got commands, headers, and libs. You should be able to use the contents of the JDK just you would elsewhere. We commonly create and use JNI libs that get loaded with LoadLibrary; I can't report personal experience with the invocation interface.

Java - Failed to Load the JNI shared Library (JDK)

I am trying to launch an application (not Eclipse) that was written in Java. When I do, I get an error that says "Failed to Load the JNI shared Library (JDK)" along with a path that points to the location of the file.
From searching Google and StackOverflow, all I can find are people saying that the Java version installed needs to match my machine. My machine is 64 bit and so is my java installation, so I don't think that is my issue.
I have also verified that C:\Program Files\Java\jre7\bin is in my path variable. Also, just for the record, I do not use Eclipse. I have also tried uninstalling and reinstalling Java an the application that was written in Java. Lastly, the file it is complaining about exists on the machine.
Does anyone know what else could be the cause of this problem?
Update:
Thanks for your responses. I got it resolved, but the resolution seems like more of a hack and goes against what I was reading earlier. I installed the 32 bit version of Java 7 along side of my 64 bit version of Java 7. I then added the path the 32 bit version to the system path variable.
After I did this, the application was able to launch. Is there an issue with having both 64 bit and 32 bit versions of Java 7 installed simultaneously?

This is an error from your application. The application uses JNI. It is complaining that it cannot load it. Why it says (JDK) only its author knows. You will have to ask the author.

There is no problem having both versions of Java installed. However, the application you were using probably shipped with a 32-bit version of the JNI library. So, it needed to be used with a 32-bit Java JRE.

JMF on 64bit java?

I know JMF is pretty much dead and whatnot, but I do know that it can still be used.
I intend to use it for personal uses and don't expect that much from it.
I have managed to install the 32bit JMF and when I run JMStudio it somehow magically works even though all of my java jres and sdks are 64-bit.
I personally believe that this proves that it CAN work.
When creating a program importing the jmf.jar as a library, my code compiles perfectly.
Only at runtime do i get any form of error with the common:
Exception in thread "VFW Request Thread"
java.lang.UnsatisfiedLinkError: JMFSecurityManager:
java.lang.UnsatisfiedLinkError: C:\Program Files
(x86)\JMF2.1.1e\lib\jmvfw.dll: Can't load IA 32-bit .dll on a AMD
64-bit platform
Obviously there is a problem with using a 32bit dll on a 64bit system.
My question is if its not compatible:
how does JMStudio work perfectly fine (it definitely uses java)
how can I fix it so that my program can run without depending on this dll
or other workarounds
Thanks a ton to anyone who has ever tried this before.
Java is definitely lacking in native specific tools such as webcams.

I think the main issue is the 64bit Java JRE/JDK trying to use the 32bit JMF, and/or JMF having a problem with the path that Windows 7 chooses as a default to install it to.
I have had success following the instructions posted here:
Oracle Forums: Install JMF on Windows 7 64bit
It basically boils down to:
Install a 32bit JRE/JDK, and ensure that this is what your code uses.
Install JMF to simple directory in the root of C: (i.e. c:\JMF2.1.1e)
Good luck!

JMFStudio is 32 bit supporting software so we must install 32bit support JDK and also Eclipse then we not get any exceptions as you mentioned in above and errors.
For my case it works fine.
and also
Try to remove unused jdk path in environment variable, if duplicate path present then also it not works fine
other wise you should re-install OS.