UnsupportedClassVersionError due to fix on org.osgi.service.prefs

[adebiasi]

The CI of CHESS fails after the fix related to #54.

The log before the issue/fix of org.osgi.service.prefs: log_ok.txt

The log after: log.txt

[adebiasi]

This is the fragment of pom.xml containing the dependences:

<profile>
			<id>Eclipse-Neon-Java8-devel</id>
			<properties>
				<!-- Tycho settings -->
				<tycho.version>1.0.0</tycho.version>
				<tycho.extras.version>1.0.0</tycho.extras.version>
				<maven.compiler.source>1.8</maven.compiler.source>
				<maven.compiler.target>1.8</maven.compiler.target>
				<xtextVersion>2.12.0</xtextVersion>
				<ecore-xcore-version>1.3.1</ecore-xcore-version>
				<ecore-xcore-codegen-version>1.2.0</ecore-xcore-codegen-version>
				<ecore-xcore-lib-version>1.1.100</ecore-xcore-lib-version>
				<mwe2Version>[2.9.0,2.9.1)</mwe2Version>
				<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
				<maven.compiler.source>1.8</maven.compiler.source>
				<maven.compiler.target>1.8</maven.compiler.target>
				<emfRuntimeVersion>2.12</emfRuntimeVersion>
				<maven.build.timestamp.format>yyMMddHHmm</maven.build.timestamp.format>
				<!-- <buildNumber>${maven.build.timestamp}</buildNumber> -->
				<chessBuildNumber>devel_${maven.build.timestamp}</chessBuildNumber>
			</properties>
			<build>
				<plugins>
					<plugin>
						<groupId>org.eclipse.tycho</groupId>
						<artifactId>target-platform-configuration</artifactId>
						<version>${tycho.version}</version>
						<configuration>
							<target>
								<artifact>
									<groupId>org.polarsys.chess.target</groupId>
									<artifactId>org.polarsys.chess.target.neon</artifactId>
									<version>${project.version}</version>
								</artifact>
							</target>
						</configuration>
					</plugin>
					<plugin>
						<groupId>org.eclipse.xtend</groupId>
						<artifactId>xtend-maven-plugin</artifactId>
						<dependencies>
							<dependency>
									<groupId>org.eclipse.jdt</groupId>
									<artifactId>org.eclipse.jdt.core</artifactId>
									<version>3.13.102</version>
								</dependency>
								<dependency>
									<groupId>org.eclipse.jdt</groupId>
									<artifactId>org.eclipse.jdt.compiler.apt</artifactId>
									<version>1.3.110</version>
								</dependency>
								<dependency>
									<groupId>org.eclipse.jdt</groupId>
									<artifactId>org.eclipse.jdt.compiler.tool</artifactId>
									<version>1.2.101</version>
								</dependency>
								<dependency>
									<groupId>org.eclipse.emf</groupId>
									<artifactId>org.eclipse.emf.codegen</artifactId>
									<version>2.11.0</version>
								</dependency>		
								<dependency>
									<groupId>org.eclipse.platform</groupId>
	  								<artifactId>org.eclipse.text</artifactId>
	  								<version>3.8.200</version>
	  								<exclusions>
										<exclusion>
								          <groupId>org.eclipse.platform</groupId>
								          <artifactId>org.eclipse.equinox.common</artifactId>
								        </exclusion>
									</exclusions>  																
								</dependency>
								<dependency>
									<groupId>org.eclipse.platform</groupId>
	  								<artifactId>org.eclipse.core.runtime</artifactId>
	  								<version>3.15.300</version>  								
									<exclusions>
										<exclusion>
								          <groupId>org.eclipse.platform</groupId>
								          <artifactId>org.eclipse.equinox.common</artifactId>
								        </exclusion>
									</exclusions>
								</dependency>
								<dependency>
									<groupId>org.eclipse.platform</groupId>
	  								<artifactId>org.eclipse.equinox.common</artifactId>
	  								<version>3.10.400</version>  
								</dependency>								
						</dependencies>
					</plugin>
				</plugins>
			</build>
		</profile>

[cdietrich]

this is a problem that is there since platform moved to java 11 some time ago.
i wonder why you run into it now.
you might want to update to a never xtext version and or apply the workarounds needed for years as can be found in
eclipse-xtext/xtext#1976

i assume you need to make sure you pin/exclude both core.runtime and equinox.common
maybe they are now transitive by a different path where they were not before

[laeubi]

you might want to update to a never xtext version

Maybe just update to a newer java version, never tycho version, never ... just an idea :-)

[cdietrich]

@laeubi the ~ 5 year old xtext version of course does not support java 11

[laeubi]

@laeubi the ~ 5 year old xtext version of course does not support java 11

Yep but that's not the only one that is "a bit outdated" her (e.g. Tycho 1.x...)

[adebiasi]

you might want to update to a never xtext version

Maybe just update to a newer java version, never tycho version, never ... just an idea :-)

We are working on the porting of CHESS, but it is not an easy job.

@cdietrich So you suggest to update the pom.xml as follows?

<dependency>
<groupId>org.eclipse.xtext</groupId>
	<artifactId>org.eclipse.xtext.xtext.generator</artifactId>
	<version>${xtextVersion}</version>
		<exclusions>
			<exclusion>
				<groupId>org.eclipse.platform</groupId>
				<artifactId>org.eclipse.equinox.common</artifactId>
			</exclusion>
			<exclusion>
				<groupId>org.eclipse.platform</groupId>
				<artifactId>org.eclipse.core.runtime</artifactId>
			</exclusion>
		</exclusions>
</dependency>

[cdietrich]

i dont remember the linked bug is too long ago, but yes you can check if it works.
you might also have to add them explicitedy
as sibling to org.eclipse.xtext.xtext.generator

eclipse-xtext/xtext#1976 (comment)
you might also have to specify explicit versions there

[adebiasi]

i dont remember the linked bug is too long ago, but yes you can check if it works. you might also have to add them explicitedy as sibling to org.eclipse.xtext.xtext.generator

Thanks.
Do you know why this issue happened just after #54?

[laeubi]

As explained it can happen anytime as no one is checking for Java-8 compat any more!

[cdietrich]

no, for everybody else it it failing for a year now

[howlger]

@adebiasi This Stack Overflow answer from @jmini explains very well what happened and also tells what can be done.