[Bug 509535] New: java.lang.NoClassDefFoundError: com/google/gson/annotations/JsonAdapter

[mickaelistria]

See https://bugs.eclipse.org/bugs/show_bug.cgi?id=509535

[svenefftinge]

@spoenemann could you check is the generated manifest contains proper imports for the mentioned package?

[spoenemann]

The generated manifest does not have an import for com.google.gson.annotations because we don't use it directly. It's used indirectly by Gson. How can the Gson code be denied access to its own classes?

See the top of the stack:

java.lang.NoClassDefFoundError: com/google/gson/annotations/JsonAdapter
	at com.google.gson.internal.bind.JsonAdapterAnnotationTypeAdapterFactory.create(JsonAdapterAnnotationTypeAdapterFactory.java:45)
	at com.google.gson.Gson.getAdapter(Gson.java:423)
	at com.google.gson.Gson.toJson(Gson.java:661)
	at org.eclipse.lsp4j.jsonrpc.json.adapters.MessageTypeAdapterFactory$Adapter.write(MessageTypeAdapterFactory.java:203)
	at org.eclipse.lsp4j.jsonrpc.json.adapters.MessageTypeAdapterFactory$Adapter.write(MessageTypeAdapterFactory.java:54)

[spoenemann]

The Gson code where the exception occurs is this:

rawType.getAnnotation(JsonAdapter.class)

Could it be that Class.getAnnotation(..) throws NoClassDefFoundError because the given annotation type is not found by the classloader of the receiver class?

[svenefftinge]

Ok, so than it seems to be an issue in the manifest of latest gson in orbit.

[spoenemann]

Should we add a package import of com.google.gson.annotations to work around it?

[mickaelistria]

Maybe the issue isn't caused by GSon per se, but by having multiple versions of GSon in the OSGi runtime (and maybe different involved bundles loading different version of the class).
cc @mniewrzal : do you get this issue when only gson 2.7 is present or only when 2 versions are avialable?

[mniewrzal]

Maybe to clarify. Problem is visible ONLY when LSP4E is installed on the top of Oxygen when two version of gson are available:

• com.google.gson_2.2.4.v201311231704.jar
• com.google.gson_2.7.0.v20161205-1708.jar

When older version (2.2.4) is removed manually then LSP4E also works ok.

With Neon.2 everything works fine.

[mickaelistria]

Ok, so maybe this highlights that gson should be marked as a singleton?

[spoenemann]

The manifest of Gson 2.7 from Orbit says

Import-Package: com.google.gson.annotations

I think this is a bug.

[dhuebner]

@spoenemann http://felix.apache.org/documentation/tutorials-examples-and-presentations/apache-felix-osgi-faq.html#should-a-bundle-import-its-own-exported-packages

[mickaelistria]

I think it is indeed the bug. Either the package should not be imported, or it should be imported with a version constraint.

[dhuebner]

@mickaelistria Than we should report it in gson issue tracker and see what they say.
@spoenemann I hope your workaround will work. If not, try to add uses com.google.gson.annotations directive to the corresponding jsp4j package. That is what helped to get rid of mixed versioned package imports in xbase lib.

[mickaelistria]

I opened google/gson#1001 to GSon

[spoenemann]

Then we should report it in gson issue tracker and see what they say.

But the manifest is generated by Orbit, not by Gson. It says:

Built-By: genie.orbit

[dhuebner]

But the meta information provided is copied from http://repo1.maven.org/maven2/com/google/code/gson/gson/2.6.2/

[dhuebner]

I just found an issue for 2.8 google/gson#957
:-/

[dhuebner]

@mickaelistria I will provide a patch for orbit gson. I tend to remove the import rather than add a version constraint. It seems to be common to import own packages in BND, but it not really common to do it in equinox.

[dhuebner]

@mickaelistria FYI https://git.eclipse.org/r/#/c/89494/1

[dhuebner]

Fix will be part of Oxygen M6
Currently available test version:
https://hudson.eclipse.org/orbit/job/orbit-recipes/135/artifact/releng/repository/target/repository/