[brailleblaster] Re: Braille Blaster and Java versions
- From: Richard Baldwin <baldwin@xxxxxxxxxxxxxxx>
- To: brailleblaster@xxxxxxxxxxxxx
- Date: Sat, 10 Mar 2012 20:13:59 -0600
My experience is that programs compiled using the 1.7 javac cannot be
executed using the 1.6 jvm. However, I have experienced no problems
executing programs compiled using the 1.6 javac and the 1.7 jvm.
As Michael mentioned, it is possible to target specific versions at compile
time. The above statement applies only if such targeting is not used.
I believe that this version compatibility approach has generally been the
case throughout the life of Java.
1.6 has been around for more than five years so I would guess that most
systems have been upgraded to that level. However, there may be some
holdouts who are still running v1.1, 1.2, 1.3, 1.4, or 1.5.
You definitely don't want to go back past 1.5 because there were major
changes between 1.4 and 1.5.
I have not yet converted to 64 bits because there are many computers around
that don't support 64 bits. I don't know what compatibility issues, if any,
may exist between 32 and 64 bit versions.
By the way, I don't use ant so I don't know if it creates any problems.
Dick Baldwin
On Sat, Mar 10, 2012 at 7:58 PM, Vic Beckley <vic.beckley3@xxxxxxxxx> wrote:
> John,
>
> Probably the reason the 32-bit version is working is that I didn't compile
> the brailleblaster.jar file. The DLLs must not be affected. Are you using
> Java 6?
>
>
> Best regards from Ohio, U.S.A.,
>
> Vic
> E-mail: vic.beckley3@xxxxxxxxx
>
>
> -----Original Message-----
> From: brailleblaster-bounce@xxxxxxxxxxxxx
> [mailto:brailleblaster-bounce@xxxxxxxxxxxxx] On Behalf Of John J. Boyer
> Sent: Saturday, March 10, 2012 8:54 PM
> To: brailleblaster@xxxxxxxxxxxxx
> Subject: [brailleblaster] Re: Braille Blaster and Java versions
>
> Vic,
>
> I'm surprissed that Java 7 isn't backward compatible with Java 6. It
> looks like the problem may be in the manifest, and could be an Ant
> problem. However, there are others on this list who are more
> knowledgeable. I know that some people are using your 32-bit version of
> BrailleBlaster 1.3.0. Hopefully someone knows of an easy fix.
>
> Questions for others. BrailleBlaster was written using Java 1.6, because
> that was what was available. Does Java 1.7 have features that would be
> useful to us? Would switching to Java 1.7 cause more compatibility
> problems?
>
> Thanks,
> John
>
> On Sat, Mar 10, 2012 at 07:30:18PM -0500, Vic Beckley wrote:
> > John,
> >
> > I am compiling Braille Blaster and the DLLs using version 7 of the Java
> JDK.
> > I am having no problems with running what I compile on the same Java
> > version. I just gave a copy of my 32-bit version to a friend to try out.
> He
> > is running Java version 6. It won't run. He gets the below error. I also
> > tried it on my laptop, which also has Java 6, and got the same error.
> >
> > Exception in thread "main" java.lang.UnsupportedClassVersionError:
> > org/brailleblaster/Main : Unsupported major.minor version 51.0
> > at java.lang.ClassLoader.defineClass1(Native Method)
> > at java.lang.ClassLoader.defineClassCond(Unknown Source)
> > 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$000(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)
> > Could not find the main class: org.brailleblaster.Main. Program will
> exit.
> >
> > Any ideas what would cause this? Will I have to compile with Java 6? If
> so,
> > will it run on Java 7?
> >
> > Is anyone running my 32-bit Windows release of Braille Blaster 1.3.0
> > successfully? If so, what Java version do you have?
> >
> >
> > Best regards from Ohio, U.S.A.,
> >
> > Vic
> > E-mail: vic.beckley3@xxxxxxxxx
> >
> >
> >
>
> --
> John J. Boyer; President, Chief Software Developer
> Abilitiessoft, Inc.
> http://www.abilitiessoft.com
> Madison, Wisconsin USA
> Developing software for people with disabilities
>
>
>
>
--
Richard G. Baldwin (Dick Baldwin)
Home of Baldwin's on-line Java Tutorials
http://www.DickBaldwin.com
Professor of Computer Information Technology
Austin Community College
(512) 223-4758
mailto:Baldwin@xxxxxxxxxxxxxxx
http://www.austincc.edu/baldwin/
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