[gentoo-user] Java "bad version number" - what to up/downgrade?

[gentoo-user] Java "bad version number" - what to up/downgrade?

[Grant]

I'm getting the following from dumphd:

"bad version number in .class file"

I gather that I may have the wrong version of something Java installed
but I don't know how that works.  Can anyone tell me what package I
should try upgrading or downgrading?

- Grant

Re: [gentoo-user] Java "bad version number" - what to up/downgrade?

[Shawn Haggett]

On Tue, 18 Nov 2008 12:04:53 pm Grant wrote:
> I'm getting the following from dumphd:
>
> "bad version number in .class file"
>
> I gather that I may have the wrong version of something Java installed
> but I don't know how that works.  Can anyone tell me what package I
> should try upgrading or downgrading?

This normally means the class file is from a new version of Java then the 
virtual machine trying to run it (i.e. class files compiled under Java 1.5, 
but your trying to run it in Java 1.4).

"java-config -L" (without quotes) will show you what virtual machines you have 
installed. On my machine it shows (the asterisk is the currently selected 
one, i.e. what will be used to run java applications):

podge@venus ~ $ java-config -L
The following VMs are available for generation-2:
1)      Blackdown JDK 1.4.2.03 [blackdown-jdk-1.4.2]
2)      Sun JDK 1.5.0.16 [sun-jdk-1.5]
*)      Sun JDK 1.6.0.07 [sun-jdk-1.6]
podge@venus ~ $

If the newest VM isn't selected as the default, read the man page for 
java-config and tell it to set the newest one as default (1.6 is the newest 
version).

Shawn

Re: [gentoo-user] Java "bad version number" - what to up/downgrade?

[Grant]

>> I'm getting the following from dumphd:
>>
>> "bad version number in .class file"
>>
>> I gather that I may have the wrong version of something Java installed
>> but I don't know how that works.  Can anyone tell me what package I
>> should try upgrading or downgrading?
>
> This normally means the class file is from a new version of Java then the
> virtual machine trying to run it (i.e. class files compiled under Java 1.5,
> but your trying to run it in Java 1.4).
>
> "java-config -L" (without quotes) will show you what virtual machines you have
> installed. On my machine it shows (the asterisk is the currently selected
> one, i.e. what will be used to run java applications):
>
> podge@venus ~ $ java-config -L
> The following VMs are available for generation-2:
> 1)      Blackdown JDK 1.4.2.03 [blackdown-jdk-1.4.2]
> 2)      Sun JDK 1.5.0.16 [sun-jdk-1.5]
> *)      Sun JDK 1.6.0.07 [sun-jdk-1.6]
> podge@venus ~ $
>
> If the newest VM isn't selected as the default, read the man page for
> java-config and tell it to set the newest one as default (1.6 is the newest
> version).
>
> Shawn

Thank you very much.  Since I'm not a Java developer, do I want jre as
opposed to jdk?

- Grabt

Re: [gentoo-user] Java "bad version number" - what to up/downgrade?

[Shawn Haggett]

On Tue, 18 Nov 2008 02:56:57 pm Grant wrote:
> >> I'm getting the following from dumphd:
> >>
> >> "bad version number in .class file"
> >>
> >> I gather that I may have the wrong version of something Java installed
> >> but I don't know how that works.  Can anyone tell me what package I
> >> should try upgrading or downgrading?
> >
> > This normally means the class file is from a new version of Java then the
> > virtual machine trying to run it (i.e. class files compiled under Java
> > 1.5, but your trying to run it in Java 1.4).
> >
> > "java-config -L" (without quotes) will show you what virtual machines you
> > have installed. On my machine it shows (the asterisk is the currently
> > selected one, i.e. what will be used to run java applications):
> >
> > podge@venus ~ $ java-config -L
> > The following VMs are available for generation-2:
> > 1)      Blackdown JDK 1.4.2.03 [blackdown-jdk-1.4.2]
> > 2)      Sun JDK 1.5.0.16 [sun-jdk-1.5]
> > *)      Sun JDK 1.6.0.07 [sun-jdk-1.6]
> > podge@venus ~ $
> >
> > If the newest VM isn't selected as the default, read the man page for
> > java-config and tell it to set the newest one as default (1.6 is the
> > newest version).
> >
> > Shawn
>
> Thank you very much.  Since I'm not a Java developer, do I want jre as
> opposed to jdk?
>
> - Grabt

Yeah, the JRE will be fine. The important thing is just which version is 
active. I do Java development, hence the JDK.

Shawn

Re: [gentoo-user] Java "bad version number" - what to up/downgrade?

[Grant]

>> >> I'm getting the following from dumphd:
>> >>
>> >> "bad version number in .class file"
>> >>
>> >> I gather that I may have the wrong version of something Java installed
>> >> but I don't know how that works.  Can anyone tell me what package I
>> >> should try upgrading or downgrading?
>> >
>> > This normally means the class file is from a new version of Java then
>> > the
>> > virtual machine trying to run it (i.e. class files compiled under Java
>> > 1.5, but your trying to run it in Java 1.4).
>> >
>> > "java-config -L" (without quotes) will show you what virtual machines
>> > you
>> > have installed. On my machine it shows (the asterisk is the currently
>> > selected one, i.e. what will be used to run java applications):
>> >
>> > podge@venus ~ $ java-config -L
>> > The following VMs are available for generation-2:
>> > 1)      Blackdown JDK 1.4.2.03 [blackdown-jdk-1.4.2]
>> > 2)      Sun JDK 1.5.0.16 [sun-jdk-1.5]
>> > *)      Sun JDK 1.6.0.07 [sun-jdk-1.6]
>> > podge@venus ~ $
>> >
>> > If the newest VM isn't selected as the default, read the man page for
>> > java-config and tell it to set the newest one as default (1.6 is the
>> > newest version).
>> >
>> > Shawn
>>
>> Thank you very much.  Since I'm not a Java developer, do I want jre as
>> opposed to jdk?
>>
>> - Grabt
>
> Yeah, the JRE will be fine. The important thing is just which version is
> active. I do Java development, hence the JDK.
>
> Shawn

Can you tell me the best way to Gentoo all of this?  I've now got:

# java-config -L
The following VMs are available for generation-2:
1)	Sun 32bit JRE 1.6.0.07 [emul-linux-x86-java-1.6]
2)	Sun JDK 1.5.0.16 [sun-jdk-1.5]
*)	Sun JDK 1.6.0.07 [sun-jdk-1.6]

and dev-java/sun-jdk in my world file, and it wasn't there before.
Also, emerge world wants to install virtual/jre-1.6.0 and
virtual/jdk-1.6.0.  Should I un-emerge sun-jdk-1.5?

- Grant