How to use Java11 (Java10) with Eclipse Plugin?

Question

If I specify JavaSE-10 as minimum execution environment in my Eclipse plugin:

I get following errors when starting my plugin as Eclipse Application:

org.osgi.framework.BundleException: Could not resolve module: org.treez.core [597]
  Unresolved requirement: Require-Capability: osgi.ee; filter:="(&(osgi.ee=JavaSE)(version=10))"
  Unresolved requirement: Require-Bundle: org.treez.javafxd3; visibility:="reexport"
    -> Bundle-SymbolicName: org.treez.javafxd3; bundle-version="1.0.0.qualifier"; singleton:="true"
       org.treez.javafxd3 [586]
         Unresolved requirement: Require-Capability: osgi.ee; filter:="(&(osgi.ee=JavaSE)(version=10))"

    at org.eclipse.osgi.container.Module.start(Module.java:444)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1634)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1613)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.doContainerStartLevel(ModuleContainer.java:1585)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1528)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1)
    at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
    at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)

I checked that

• Java10 is reverenced under Installed JREs
• 10 is selected as compliance level

I use Oxygen.3a Release (4.7.3a) Build id: 20180405-1200

=>Is this a bug in eclipse equinox?

=>What else can I check to resolve this issue?

If I remove JavaSE-10 from the minimum execution environment settings I am able to start the Eclipse Application and the plugin seems to work fine.

When I export the plugin I get following warning:

# 25.04.18, 12:25:40 MESZ
# Eclipse Compiler for Java(TM) v20180330-0919, 3.13.102, Copyright IBM Corp 2000, 2015. All rights reserved.
option -bootclasspath not supported at compliance level 9 and above

When I try to use the plugin after installing it from my update page, I get a ClassNotFoundException:

...
Caused by: java.lang.ClassNotFoundException: org.treez.views.tree.TreeViewPart cannot be found by org.treez.views_1.0.0.201804191641
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:484)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:395)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:387)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:150)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.loadClass(EquinoxBundle.java:564)
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:174)
    ... 114 more

If I use Java8 everything works fine.

Related questions:

• Java 8 & Missing required capability Require-Capability: osgi.ee; filter="(&(osgi.ee=JavaSE)(version=1.8))"

• How to set up java 10 in Eclipse Oxygen?

• How to add org.eclipse.swt (and other plugin dependencies) as an automatic Java9 module?

Answer 1

It looks like Eclipse OSGi does not support Java SE 10 yet. I downloaded the latest Eclipse Oxygen 4.7.3a and opened plugins/org.eclipse.osgi_3.12.100.v20180210-1608.jar. The last supported profile was JavaSE-9.

So, you have two choices here:

• Wait until OSGi officially supports JavaSE-10 profile.
• If you really want to write a plugin with Java 10 and you have control over the plugins folder (e.g. you develop an Eclipse RCP application), open the OSGI jar and add a new profile JavaSE-10. To do this, you can copy JavaSE-9.profile to JavaSE-10.profile and fix corresponding lines in the new file. Also, you must add a new line to profile.list.

Answer 2

Since OSGi 4.3, the most appropriate way to specify a minimum Java version is using the Required-Capability header, as in:

Require-Capability: osgi.ee;filter:="(&(osgi.ee=JavaSE)(version>=1.10))"

I have had success fixing the reported error by replacing all occurrences of Bundle-RequiredExecutionEnvironment with the above line. In PDE, you may get a warning on the manifest file, but it can be safely ignored. Product validation and product exports seems to work without issue.

The semantic of the BREE header required that an execution environnement descriptor be provided by the OSGi implementation for each specific release of the JRE. In Equinox, this used to be defined through ".profile" files; these profiles have been supported by Equinox up to JavaSE-9, but it has been announced that Equinox they would no longer provide profiles for newer releases of Java.

The Tycho community has handled this issue on their side by creating their own Java 10 profile, but it can't be used directly from PDE. The P2 community is considering copying Tycho's Java 10 profile, but this has been stalled for a long time. I'm not sure how P2 reacts at present when fed bundles that do not contains the BREE header.

Answer 3

What worked for me as a work around was to

• Remove the required version entries from the manifest files and ignore the corresponding warnings

• Activate the option "Use class files compiled in the workspace" in the export wizard:

(Therefore I assume that something goes wrong during the compilation step of the export wizard if that option is not applied.)

I used Java 11.0.1 and Eclipse SimRel 2018-09 (plus Java11 support plugin)