Java compatibility

Discussion:

Java compatibility

ocs@ocs

2018-10-01 03:59:26 UTC

Hi there,

is is possible that WOnder 7 is not compatible with Java 6? Whatever I try, I can't find any description on the Web; what I am getting though is an error

===
Exception in thread "main" java.lang.UnsupportedClassVersionError: er/extensions/appserver/ERXApplication : Unsupported major.minor version 52.0
===

on a client's server, where there is

===
53 # java -version
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-10M4609)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode)
54 #
===

On all my machines, where happen to be Javas 8-10, the application runs all right.

Thanks for any insight,
OC

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Chuck Hill

2018-10-01 04:09:00 UTC

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I don't recall what the source level backwards compatibility is. But that message means you are trying to use .class files compiled for Java 8 on an earlier JVM (1.6 clearly). You will need to either upgrade the server or re-compile from source targeting 1.6.

Chuck

P.S. Java 1.6?!!?

On 2018-09-30, 8:59 PM, "Webobjects-dev on behalf of ***@ocs" <webobjects-dev-bounces+chill=***@lists.apple.com on behalf of ***@ocs.cz> wrote:

Hi there,

is is possible that WOnder 7 is not compatible with Java 6? Whatever I try, I can't find any description on the Web; what I am getting though is an error

===
Exception in thread "main" java.lang.UnsupportedClassVersionError: er/extensions/appserver/ERXApplication : Unsupported major.minor version 52.0
===

on a client's server, where there is

===
53 # java -version
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-10M4609)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode)
54 #
===

On all my machines, where happen to be Javas 8-10, the application runs all right.

Thanks for any insight,
OC

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Johann Werner

2018-10-01 08:12:51 UTC

Permalink

The compatibilities are listed in the github Wiki: https://github.com/wocommunity/wonder/wiki

For Java 6 you would have to use Wonder 6 as Wonder 7 uses a lot of libs that are not compatible with Java 6 anymore.

jw

Post by ***@ocs
Hi there,
is is possible that WOnder 7 is not compatible with Java 6? Whatever I try, I can't find any description on the Web; what I am getting though is an error
===
Exception in thread "main" java.lang.UnsupportedClassVersionError: er/extensions/appserver/ERXApplication : Unsupported major.minor version 52.0
===
on a client's server, where there is
===
53 # java -version
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-10M4609)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode)
54 #
===
On all my machines, where happen to be Javas 8-10, the application runs all right.
Thanks for any insight,
OC

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Jesse Tayler

2018-10-01 12:03:38 UTC

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I think you get that when your Eclipse is set to a higher or perhaps different JAVA than your server.

Is that possible?

Post by Johann Werner
The compatibilities are listed in the github Wiki: https://github.com/wocommunity/wonder/wiki
For Java 6 you would have to use Wonder 6 as Wonder 7 uses a lot of libs that are not compatible with Java 6 anymore.
jw

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ocs@ocs

2018-10-01 12:40:24 UTC

Permalink

Gentlemen, thanks!

Aha, I see.

Post by Johann Werner
I don't recall what the source level backwards compatibility is. But that message means you are trying to use .class files compiled for Java 8 on an earlier JVM (1.6 clearly). You will need to either upgrade the server or re-compile from source targeting 1.6.

I am using the switches “target=1.6 source=1.6” when compiling, and it seems to work OK; nevertheless, of course, the pre-compiled Wonder libraries were the culprit (and given Johann's answer and the wiki page, there would be no point trying to re-compile Wonder for 1.6).

Post by Johann Werner
P.S. Java 1.6?!!?

Well, my client sticks with Mac OS X Server 10.6 (and I do not blame him; from 10.7 up it went downhill, Apple started to cripple the server services, to add lots of unnecessary bloatware, etc) Alas, it is also the last one where Apple managed Java themselves, and there does not seem to be a reliable and clean way to upgrade Java in 10.6 anymore :(

Thanks and all the best,
OC

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