[OHFJIRA-84] : java 11 runtime compatibility

[kkovarik]

Support for JDK 11 runtime

With these added libraries, openhub is able to run with java 11 runtime.

Details

Main issue with backward compatibility is removal of some Java EE APIs:
https://cr.openjdk.java.net/~iris/se/11/spec/fr/java-se-11-fr-spec/#APIs-removed

these apis were marked as deprecated in java 9, removed entirely in java 11.
https://stackoverflow.com/questions/43574426/how-to-resolve-java-lang-noclassdeffounderror-javax-xml-bind-jaxbexception-in-j

Following dependencies were added, as they are required for openhub library stack:

javax.xml.bind:jaxb-api
com.sun.xml.bind:jaxb-core
com.sun.xml.bind:jaxb-impl
javax.xml.ws:jaxws-api
com.sun.xml.messaging.saaj:saaj-impl
com.sun.activation:javax.activation

Versions used are the ones used in java 8 runtime (when possible).

Known issues

Warning during spring context startup:

matching: class path resource [sp_h2_server.xml]
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.springframework.cglib.core.ReflectUtils$1 (jar:file:/home/app.war!/WEB-INF/lib/spring-core-4.3.20.RELEASE.jar!/) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain)
WARNING: Please consider reporting this to the maintainers of org.springframework.cglib.core.ReflectUtils$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

Caused by spring framework, does seem to be warning only, will be resolved in Spring 5.1 (https://jira.spring.io/browse/SPR-15859). Warning should be resolved with migration to Spring Boot 2.x.

[coveralls]

Coverage increased (+0.1%) to 67.423% when pulling 5df51b9 on feature/OHFJIRA-84-java-compatibility into 4ece392 on develop.

[pjuza]

I have Java 8 and Tomcat 8.0.20 and I'm not able to start application server - the following error occurs:

06-Nov-2018 22:31:26.961 SEVERE [RMI TCP Connection(2)-127.0.0.1] org.apache.catalina.startup.ContextConfig.processAnnotationsJar Unable to process Jar entry [module-info.class] from Jar [jar:file:/Volumes/Obelix/projects/openhub-framework/war/target/openhub/WEB-INF/lib/jaxws-api-2.3.0.jar!/] for annotations
org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 19

It's caused by updating the JAX-WS libraries of my current project to version 2.3.0, see https://blog.doubleslash.de/unable-to-process-jar-entry-module-info-class-from-jar/

Maybe it's time to leave Java 8 (also Java 9 has reached end of support) and move forward to Java 10 and higher but we have to change documentation at least (https://openhubframework.atlassian.net/wiki/spaces/OHF/pages/33608/Getting+started)

[hanusto]

But it is incompatible change. We should ship that in next major version. Why we increase version of Jax-libs? It is not possible to use the same included in Java 8?

[kkovarik]

It is not issue of java 8 runtime itself, it is caused by the tomcat 8.x. I have changed versions of libraries, should improve compatibility with older versions.

[pjuza]

I have tested with Tomcat 8.0 and 8.5 and it works fine. Great 👍