I would agree about what versions to use. Java6 probably is sufficient, but may be just state that Java6 is required in system requirements. Java5 I believe is no longer supported by Oracle. I too probably would not say go back further than Java5 for support, there were significant improvements and its extremely old now so anyone running older than that you probably couldn’t guess what version they would be using. Michael Whapples From: Richard Baldwin Sent: Sunday, March 11, 2012 2:13 AM To: brailleblaster@xxxxxxxxxxxxx Subject: [brailleblaster] Re: Braille Blaster and Java versions 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/