Source not found: The source attachment does not contain the source........

Question

Source not found: The source attachment does not contain the source for the file ClassLoader.Class
Hey,
I'm running eclipse Version: 3.2.2 Build id: M20070212-1330, on a Vista Home Premium Toshiba laptop. Everything was working fine before i installed the Java JDK 5 and JDK 6. Now all of sudden when i try to run one my programs that worked in the past i get the following error:
java.lang.UnsupportedClassVersionError: Bad version number in .class file
     at java.lang.ClassLoader.defineClass1(Native Method)
     at java.lang.ClassLoader.defineClass(Unknown Source)
     at java.security.SecureClassLoader.defineClass(Unknown Source)
     at java.net.URLClassLoader.defineClass(Unknown Source)
     at java.net.URLClassLoader.access$100(Unknown Source)
     at java.net.URLClassLoader$1.run(Unknown Source)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.net.URLClassLoader.findClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Exception in thread "main"
I'm not sure where to go from here...I've looked up a few articles that mention going into some system.ini files...etc... to make sure the variable are ok but i feel like i'm getting in over my head.
Thanks in advance for your thoughts,
Struggling to Run

Answer 1

Ok...after I thought everything was going well enough.... problems are arising.
Here's where I'm at and that will include how i got a "nano" error. After a lot of late night messing around I ended up installing a few important component that seem to have done some good. Firstly i installed j2sdk-1_4_2_18-windows-i586-p and ended up with a few good things. Windows was happy when i changed the path variables in the environment setting to point to the newly created c:\program files\java\j2re1.4.2_18\bin folder. This allowed me to start up eclipse properly and use some functions in CMD. In CMD when i use the command java -version it reads Java version 1_.4_.2_1_8. Next i installed the j2sdk-1_4_2_13 jre 1.6.0 environment and ended up with a new folder in C:\Program Files\Java\jre1.6.0 as well.
with the two environments installed i thought i was ready fro the next step.
I got started on eclipse and now that it was opening i was feeling good. Next i opened window --> preferences --> java --> installed jre's and i started adding things like crazy. My current list of comprised of many things which I'm certain should all be there at this point so I'll list them:
j2sdk1.4.2_13 - C:\j2sdk1.4.2_13
j2re1.4.2_18 - C:\Program Files\Java\j2re1.4.2_18
j2sdk1.4.2_18 - C:\j2sdk1.4.2_18\jre
j2sdk1.6.0 - C:\Program Files\Java\jre1.6.0
jdk1.6.0 - C:\Program Files\Java\jdk1.6.0
I've set the preferred jre to be set to jdk1.6.0 - C:\Program Files\Java\jdk1.6.0 and it seems to work for all of my programs that do not have the input.scanner. However for the projects that do have this method i get a few different errors:
1___________
java.lang.NoClassDefFoundError: couponCounter/CouponCounter
Exception in thread "main"
2__________
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
     Syntax error, insert "}" to complete ClassBody
     at BensCalculator.main(BensCalculator.java:112)
Now i feel like the second error is lying to me because i know that bit of code is written properly.... i believe it is related to a problem not locating the proper classes.
Anyhow I'm still pushing along but some help at this point would be much appreciated. It's very weird some things with the scanner are working now..... I don't know I'm not totally convinced yet everything is OK.
Thank you