Can't open .jar file, says it cannot be launched, Help?

Question

Level 1

5 points

Can't open .jar file, says it cannot be launched, Help?

I'm trying to download this mod for a game called minecraft. It involves opening a jar file to begin the installation, but everytime i click on the jar file it comes up with this message: The Java JAR file “YOGBOX Installer.jar” could not be launched. Check the Console for possible error messages. I have checked the Console and there doesn't seem to be any recent messages. I have tried opening the file with a different application than the default Java launcher, but it doesn't open the installation window i need. Please help, i have tried all i could. Any ideas?

MacBook, Mac OS X (10.5.8)

Posted on Jul 9, 2011 7:58 PM

Reply

Answer 1

Best reply

Bob Lang1

Level 5

4,090 points

Jul 10, 2011 4:48 PM in response to Hamptonw

Put the jar file on the desktop. Now open Applications/Utilities/Terminal and type the following commands, putting a new line after each one:

cd

cd Desktop

java -version

java -jar YOGBOX\ Installer.jar

(When you type the last command, you should be able to type java -jar YOG then press TAB and it will fill in the rest of the name for you. Since the jar file name has an embedded space you need a backslash just before the space in the file name).

Whatever error messages you get, cut and paste them back here

Bob

Reply

Answer 2

Hamptonw Author

Level 1

5 points

Jul 10, 2011 6:25 PM in response to Bob Lang1

This is what popped up after i typed all that in :

Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad version number in .class file

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(ClassLoader.java:676)

at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)

at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)

at java.net.URLClassLoader.access$100(URLClassLoader.java:56)

at java.net.URLClassLoader$1.run(URLClassLoader.java:195)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:188)

at java.lang.ClassLoader.loadClass(ClassLoader.java:317)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:280)

at java.lang.ClassLoader.loadClass(ClassLoader.java:252)

at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:375)

Reply

Answer 3

Bob Lang1

Level 5

4,090 points

Jul 11, 2011 1:35 AM in response to Hamptonw

The jar file was created using a later version of Java than you have on your system. Either you need to bring your version of Java up to date, or you need to run Applications/Utilities/Java Preferences and ensure that the 32 and 64 bit versions of Java SE 6 are selected and are dragged to the top of the list.

Bob

Reply

Answer 4

Hamptonw Author

Level 1

5 points

Jul 11, 2011 7:12 AM in response to Bob Lang1

There is no update for Java, so i assume it is the latest version. And I only have a 64 bit version of Java SE 6, i don't have a 32 bit. But all of them were checked and the SE 6 was at the top already.

Reply

Answer 5

Hamptonw Author

Level 1

5 points

Jul 11, 2011 7:15 AM in response to Hamptonw

Oh wait! Nevermind, it wasn't at the top. It worked! Thanks so much, i really appreciate the help!

Reply

Answer 6

Jul 25, 2011 1:37 AM in response to Bob Lang1

I did this , and it looked like it worked but now my Minecraft wont open , have any idea what happend ?

Reply

Answer 7

Bob Lang1

Level 5

4,090 points

Jul 25, 2011 2:46 AM in response to Jennifer561

Hi Jennifer

I think it's best to ask this question again by starting a new discussion in the System Software > Mac OS X v10.7 Lion or Mac OS X v10.6 Snow Leopard section as appropriate.

Bob

Reply

Answer 8

Jul 25, 2011 12:59 PM in response to Bob Lang1

I would like to , but as long as I was here I thought I would just write it since you already knew . But if you have any ideas could you please tell me ?

Reply

Answer 9

Bob Lang1

Level 5

4,090 points

Jul 25, 2011 2:54 PM in response to Jennifer561

Jennifer561 wrote:

I would like to , but as long as I was here I thought I would just write it since you already knew . But if you have any ideas could you please tell me ?

Sorry, I have no ideas. I think it needs someone who's familiar with Minecraft to suggest a solution. When you post your question, it might be a good idea to look in Applications/Utilities/Console to see if there are any error messages logged when you try to start Minecraft. Post these at the same time that you post your question.

Bob

Reply

Answer 10

Apr 21, 2016 5:23 PM in response to Bob Lang1

How do you get to java prefrences?

Reply