build: Drop OSGi support (#31747)

* build: Drop OSGi support #28304

* Cleaner inclusion of JDK9+ classes

* migration guide, drop osgi page

.gitignore

@@ -50,7 +50,6 @@ akka-docs-dev/rst_preprocessed/
 akka-docs/_build/
 akka-docs/exts/
 akka-docs/rst_preprocessed/
-akka-osgi/src/main/resources/*.conf
 akka.sublime-project
 akka.sublime-workspace
 akka.tmproj

akka-actor/src/main/scala/akka/actor/ActorSystem.scala

@@ -997,7 +997,6 @@ private[akka] class ActorSystemImpl(
       "akka-distributed-data",
       "akka-testkit",
       "akka-multi-node-testkit",
-      "akka-osgi",
       "akka-persistence",
       "akka-persistence-query",
       "akka-persistence-shared",

akka-docs/src/main/paradox/project/index.md

@@ -10,7 +10,6 @@
 * [../common/may-change](../common/may-change.md)
 * [ide] (../additional/ide.md)
 * [lombok](immutable.md)
-* [osgi](../additional/osgi.md)
 * [migration-guides](migration-guides.md)
 * [rolling-update](rolling-update.md)
 * [issue-tracking](issue-tracking.md)

akka-docs/src/main/paradox/project/migration-guide-2.7.x-2.8.x.md

@@ -0,0 +1,21 @@
+---
+project.description: Migrating to Akka 2.8.
+---
+# Migration Guide 2.7.x to 2.8.x
+
+Akka 2.8.x is binary backwards compatible with 2.7.x with the ordinary exceptions listed in the
+@ref:[Binary Compatibility Rules](../common/binary-compatibility-rules.md).
+
+No configuration changes are needed for updating an application from Akka 2.7.x to 2.8.x.
+
+Rolling updates of Akka Cluster from Akka 2.7.x to 2.8.x is fully supported.
+
+No deprecated features or APIs have been removed in Akka 2.8.x, except for OSGi
+
+
+## OSGi no longer supported out of the box
+
+OSGi packaging and support in Akka has been dropped.
+
+Projects using OSGi will need to re-package or find another solution for using OSGi, you can find some possible hints
+in issue: https://github.com/akka/akka/issues/28304

akka-docs/src/main/paradox/project/migration-guides.md

@@ -7,7 +7,8 @@ project.description: Akka version migration guides.
 
 @@@ index
 
-* [migration-guide-2.5.x-2.6.x](migration-guide-2.6.x-2.7.x.md)
+* [migration-guide-2.7.x-2.8.x](migration-guide-2.7.x-2.8.x.md)
+* [migration-guide-2.6.x-2.7.x](migration-guide-2.6.x-2.7.x.md)
 * [migration-guide-2.5.x-2.6.x](migration-guide-2.5.x-2.6.x.md)
 * [migration-guide-old](migration-guide-old.md)