NoClassDefFoundError: sun.misc.Unsafe since version 2.8.3

[cnsgithub]

After upgrading gson to version 2.8.3 I receive a NoClassDefFoundError when starting up my WildFly 12 server.

Reproducer:

public class Foo {
   private static final Gson gson = new GsonBuilder().create();
}

Stacktrace:

Caused by: java.lang.NoClassDefFoundError: sun/misc/Unsafe
	at com.google.gson//com.google.gson.internal.reflect.UnsafeReflectionAccessor.getUnsafeInstance(UnsafeReflectionAccessor.java:47)
	at com.google.gson//com.google.gson.internal.reflect.UnsafeReflectionAccessor.<init>(UnsafeReflectionAccessor.java:31)
	at com.google.gson//com.google.gson.internal.reflect.ReflectionAccessor.<clinit>(ReflectionAccessor.java:36)
	at com.google.gson//com.google.gson.internal.ConstructorConstructor.<init>(ConstructorConstructor.java:51)
	at com.google.gson//com.google.gson.Gson.<init>(Gson.java:205)
	at com.google.gson//com.google.gson.GsonBuilder.create(GsonBuilder.java:597)
	at deployment.Foo.ear//Foo.<clinit>(Foo.java:24)
...
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:488)
	at java.base/java.lang.Class.newInstance(Class.java:558)
	at org.jboss.as.weld.common//org.jboss.as.weld.deployment.WeldPortableExtensions.tryRegisterExtension(WeldPortableExtensions.java:53)
	at org.jboss.as.weld//org.jboss.as.weld.deployment.processors.WeldPortableExtensionProcessor.loadAttachments(WeldPortableExtensionProcessor.java:119)
	at org.jboss.as.weld//org.jboss.as.weld.deployment.processors.WeldPortableExtensionProcessor.deploy(WeldPortableExtensionProcessor.java:79)
	at org.jboss.as.server@4.0.0.Final//org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:144)
	... 8 more

Workaround in WildFly 12 module.xml:

<module xmlns="urn:jboss:module:1.1" name="com.google.gson">
    <resources>
        <resource-root path="gson-2.8.3.jar"/>
    </resources>
    <dependencies>
        <module name="sun.jdk" export="true" >
            <imports>
                <include path="sun/misc/Unsafe" />
            </imports>
        </module>
    </dependencies>   
</module>

Question:
Why did gson introduce this weird dependency?

[inder123]

Are you using Java 9? This code path gets exercised only for Java 9.
This stacktrace is harmless as we check whether Sun's Unsafe allocator is available. If unsafe allocator is not available, we use something else.

I will remove this spurious stacktrace in the next release.

[inder123]

Fixed in Gson 2.8.4 through #1306.
Please try it out and let me know if you still need the sun.misc.Unsafe dependency.

[cnsgithub]

Yes, I am using Java 9.

And I am not getting this stacktrace any longer with gson 2.8.4. Thanks for fixing and releasing it so quickly.