[SOLVED] Minecraft and Java

[harry617]

Hi all. First off I'd like to thank everyone who helped me get my netbook working a few weeks ago.
Okay, so I play this cool game called Minecraft. It uses Java, and I can play the game in my internet browser, but not on my computer.
Am I being too vague?
Do you guys play Minecraft?
Oh yeah, how can I play the file on my computer?
Thanks.

[Snowhog]

Re: Minecraft and Java

Could be helpful: Minecraft for Linux - Black Screen Fix

[harry617]

Re: Minecraft and Java

Ok. I tried what he said but I didn't get anything working.
Having said that, it was like it was written in a different language to me.
Thanks

[rfakhrai]

Re: Minecraft and Java

You're being a bit vague. Did you read the instructions under the Linux download on this page? It's a pretty simple (and fun) java game so just follow those directions and report back if you have errors.

EDIT:
sun-java6-jre is the package that you might not have. Install it in your package manager and in console

java minecraft.jar

[lmilano]

Re: Minecraft and Java

You're being a bit vague. Did you read the instructions under the Linux download on this page? It's a pretty simple (and fun) java game so just follow those directions and report back if you have errors.

EDIT:
sun-java6-jre is the package that you might not have. Install it in your package manager and in console

java minecraft.jar

Yes, that works here (I get a pop-up asking for login info)

I had to use the more verbose syntax suggested in that page:

java -Xmx1024M -Xms512M -cp minecraft.jar net.minecraft.LauncherFrame

[rfakhrai]

Re: Minecraft and Java

ok cool. enjoy.

[lmilano]

Re: Minecraft and Java

Thanks, I actually don't play games, I just tested for Harry 8)

[harry617]

Re: Minecraft and Java

Haha! Thanks man.
I'm sure I've installed java becuase I can play it in my browser.

harry@Harry-Netbook:~$ java minecraft.jar
Exception in thread "main" java.lang.NoClassDefFoundError: minecraft/jar
Caused by: java.lang.ClassNotFoundException: minecraft.jar
at java.net.URLClassLoader$1.run(URLClassLoader.java: 217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:3 21)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 66)
Could not find the main class: minecraft.jar. Program will exit.
harry@Harry-Netbook:~$ java -Xmx1024M -Xms512M -cp minecraft.jar net.minecraft.LauncherFrame
Exception in thread "main" java.lang.NoClassDefFoundError: net/minecraft/LauncherFrame
Caused by: java.lang.ClassNotFoundException: net.minecraft.LauncherFrame
at java.net.URLClassLoader$1.run(URLClassLoader.java: 217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:3 21)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 66)
Could not find the main class: net.minecraft.LauncherFrame. Program will exit.
harry@Harry-Netbook:~$

I really have no idea what I'm doing...

[skunk]

Re: Minecraft and Java

try

java -jar minecraft.jar

[lmilano]

Re: Minecraft and Java

Maybe the wrong java executable is being called? What if you replace "java" by "/usr/lib/jvm/java-6-openjdk/jre/bin/java"

This is what I have in my system:

lmilano@grisell:~$ whereis java
java: /usr/bin/java /usr/share/java /usr/share/man/man1/java.1.gz
lmilano@grisell:~$ ls -l /usr/bin/java
lrwxrwxrwx 1 root root 22 2010-09-11 15:29 /usr/bin/java -> /etc/alternatives/java*
lmilano@grisell:~$ ls -l /etc/alternatives/java
lrwxrwxrwx 1 root root 40 2010-09-11 15:29 /etc/alternatives/java -> /usr/lib/jvm/java-6-openjdk/jre/bin/java*

I think it is worth checking that you have the java version indicated by rfakhrai

[harry617]

Re: Minecraft and Java

When I try it says "unable to access jar file minecraft.jar"

harry@Harry-Netbook:~$ /usr/lib/jvm/java-6-openjdk/jre/bin/java -version
java version "1.6.0_20"
OpenJDK Runtime Environment (IcedTea6 1.9.5) (6b20-1.9.5-0ubuntu1)
OpenJDK Server VM (build 19.0-b09, mixed mode)

I don't think I have the right version...

[rfakhrai]

Re: Minecraft and Java

no it looks like you have the right java. the trick is to

cd

into the directory that minecraft.jar is in before you issue the java command. Alternately you can use provide the full path to minecraft.jar when you issue the command.

[Snowhog]

Re: Minecraft and Java

I don't think he does. Look closely, and you'll see that he has the JDK package of java installed, not the JRE. Not certain that that would make a difference, but the JDK is the Java Development Toolkit and the JRE is the Java Runtime environment, an implementation of the Java Virtual Machine which actually executes Java programs. JDK does include JRE (What is the difference between JRE and the Java SE platform?), according to the link, but...

If it were me, and instructions told me that I needed JRE, that's what I would install.

[rfakhrai]

Re: Minecraft and Java

Thanks for pointing out the specifics Snowhog. harry617 never did report back if he had the JRE package. He assumed that he did.

harry617: I think this could simply be solved by opening your package manager and searching for java to see what you have installed.
sun-java6-jre is what you need. Do you have it? IF you have that package, what is the result of

java -jar /path/to/minecraft.jar

?

[rfakhrai]

Re: Minecraft and Java

I HAVE JUST TESTED THIS ON MY MACHINE AND IT WORKS
I don't know why I'm obsessed with solving this problem but here is the method:
1.

sudo apt-get install sun-java6-jre

(which also installs sun-java6-bin and jdk)
2.

cd <directory where minecraft.jar is>

3.

java -jar minecraft.jar

If you have problems with this method, please post the error output. Admittedly I've only played this game online but it is addicting and I'd like to see you get it working