Develop Reference

Getting error in installing scala

i follow the tutorial https://class.coursera.org/progfun-005/lecture/21
to install Scala.
I have already java install in it.As the tutorial guides i download the latest sbt and install it.
But when i am trying to run in command prompt by typing
sbt sbtVersion it gives an error that "Files was unexpected at this time"
I am new in this so ignore if i am making any silly error

Download the jar and run it using java -jar /location/of/the/downloaded/jar/from/the/previous/link -- leave a comment if you have further problems.

Eclipse 'Installing Software' - chmod failed

I'm new to Java and Eclipse and I'm not sure what this error message means:
*An error occurred while installing the items session context was:
(profile=epp.package.java,
phase=org.eclipse.equinox.internal.p2.engine.phases.Install,
operand=null --> [R]com.sap.ide.support.feature_root.gtk.linux.x86_64
1.11.1, action=org.eclipse.equinox.internal.p2.touchpoint.natives.actions.ChmodAction).
The action chmod failed - file
/opt/eclipse/collectSupportInformation.sh does not exist*
This happened while I was trying to install a ui tool. I've used Help->Install New Software before and it worked just fine then but now I'm getting this error no matter what I'm trying to install (I tried several different tools). What am I supposed to do?
I'm using Eclipse Luna on Ubuntu 14.04

I was having this issue on my mac. I got it working by moving the Eclipse app to the Applications folder (I was running it from Downloads).

Try the below steps:-
1) Restart your eclipse by using clean flag -> ./eclipse -clean
2) Turn off usage data collection by going to preference->usage data collection-> turn off
3) make sure the user who is running eclipse having read write permission to dir /opt/eclipse, or just execute the command chmod -R 777 /opt/eclipse (Once problem is resolved you can again change the proper mode, 777 is just for trying to fix the issue).
Hope it will help you to resolve the issue.Please update if you facing any issue to follow the above steps.

I've got something similar but under Windows 8.1 and the fix was to close the Eclipse IDE and then "Run as Administrator", then run the updates!

Try downloading full package through eclipse.org direct link instead of through Installer.

I had the same problem when I was "opening with Archiver" instead of saving first to disk. If first I save the tar.gz to disk, then untar it and run the eclipse-inst, all is fine

Issue Running MatlabControl

I have successfully compiled the "Hello World" example found on this link: http://code.google.com/p/matlabcontrol/wiki/Walkthrough.
However, when I try to run it, I get the following exception:
Exception in thread "main" matlabcontrol.MatlabConnectionException:
Could not launch MATLAB. Command: [matlab, -desktop, -r, javaaddpath '/usr/local/MATLAB/R2011a/java/jar/matlabcontrol-4.0.0.jar'; matlabcontrol.MatlabClassLoaderHelper.configureClassLoading(); javarmpath '/usr/local/MATLAB/R2011a/java/jar/matlabcontrol-4.0.0.jar'; matlabcontrol.MatlabConnector.connectFromMatlab('PROXY_RECEIVER_6eb278d0-1401-4b9c-b9e4-80512708f9b7', 2100);].
I have Matlab2011a installed in Ubuntu 11.10.
Could anyone point out where the problem could possibly be?

If you check the compatibility between OS and MATLAB version?
https://code.google.com/p/matlabcontrol/wiki/Compatibility
I suggest that you should update matlabcontrol-4.0.0.jar to latest version matlabcontrol-4.1.0.jar which can be downloaded from website.
Remember to open MATLAB before running the code and check if you have included all related jar files (jmi.jar...etc)to the java build path.

That exception that you posted suggests that you need to add Matlab to your system path. Check online guides on how to do that on Ubuntu.

Java is not working in my PC

I had installed Java in my PC and it was working perfectly. Suddenly something went wrong and now I m not able to open swing applications and its showing the error 'Java not found'. But I can run the Eclipse IDE which also needed Java to run. So I decide to reinstall the Java, but when I tried to uninstall the Java it shows the Error 1723 - There is a problem with this Windows Installer Package. So I have installed a new JDK in another location and set the PATH. Still I am not able to run the Swing application.
Can anybody help me on this?

How are you running your swing application?
If it's from the command line like java mySwingApp and you're getting java not found then your PATH isn't set properly. Make sure that the java/bin directory is on your PATH not just the top level directory. You can test your PATH by just typing java in a console window - it should print the java help page.
If you're not running from a terminal like above, then you may need to set a JAVA_HOME environment variable which points to your java installation folder. Here's a tutorial on setting JAVA_HOME
Setting JAVA_HOME
Hope this helps,
Will

This is close to jakob's answer, about trying to get your Java install setup correctly again, just with a little more detail.
I had a similar problem on my Windows 7 box where I was trying to uninstall Java and do a clean install of a newer version. Something got messed up and I would get the 1723 error message during the uninstall and attempted reinstall. Here's information about how I was able to fix the problem, and maybe this will help you:
Look at the log files for the uninstall/reinstall. On Windows 7 they can be found at c:\users\username\AppData\Local\Temp\
The java_install.logdidn't show any extra information, but I had several MSI##### log files that contained error messages about the failed uninstall. The message was: Error 1723.There is a problem with this Windows Installer package. A DLL required for this install to complete could not be run. Contact your support personnel or package vendor. Action UninstallJRE, entry: MSIUninstallJRE, library: C:\Program Files\Java\jre6\bin\regutils.dll
There was indeed no regutils.dll file, and not even the bindirectory was there. So I copied over a regutils.dll file from another computer, ran the uninstaller, and it worked. Then the new clean install of Java also worked.
So take a look at your logfiles and hopefully that will give you more detailed information about the 1723 error.

This usally happens when you delete Java files manually.
If you try to uninstall Java and it fails, it generates a log file.
Should be in C:\Users[Username]\AppData\Local\Temp
Almost at the end the missing file(s) can be found.
Try to copy that file(s) from a working installation to your computer.
Then you should be able to uninstall your Java and install a new version.

Getting error "bash: appletviewer: command not found".

I'm trying to learn Java and I'm having problems with the appletviewer command. I am using openSUSE 11 and am able to compile and run normal java programs but when I issue the appletviewer command I'm getting the following error "bash: appletviewer: command not found".
I have set the PATH variable in the .bashrc file. so the problem is not that of the path. This can also be verified from the fact that javac and java commands are working normally. I have googled and tried many said resolution but none is working. I have even tried moving the files to the bin folder and running the command from there.
So what may the cause of this? Isn't appletviewer designed to work in linux? And FYI I have replaced the OpenSDK and IcedTea versions with the jdk1.6.0_14 version from the sun site. Please help.
Thanks
Chris

As a test, do the following:
$which java
$which appletviewer
Check to see if the paths are different. If the second command gives no output, appletviewer may not even be installed (or can't be located by your system).

You need to install java-1_6_0-sun-devel-1.6.0.u14-0.2.1
$ sudo zypper install java-1_6_0-sun-devel
You will find it in the openSUSE-11.1-Non-Oss repository.