Jdep issue on org.springframework.objenesis.instantiator.sun.UnsafeFactoryInstantiator [SPR-15668]

[spring-projects-issues]

rajendra rathore opened SPR-15668 and commented

Hi Team,
I ran the JDep on spring core 4.3.2 version and found that org.springframework.objenesis.instantiator.sun.UnsafeFactoryInstantiator uses sun.misc.Unsafe, and it says that it is JDK internal API (jdk.unsupported). so please let me know your plan for that class.

Thanks
Rajendra Rathore

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Affects: 4.3.2

Issue Links:

• Upgrade to Objenesis 2.5 [SPR-15146] #19712 Upgrade to Objenesis 2.5
• Upgrade to Objenesis 2.6 for Google App Engine Standard on Java 8 and for better JDK 9 support [SPR-15600] #20159 Upgrade to Objenesis 2.6 for Google App Engine Standard on Java 8 and for better JDK 9 support

[spring-projects-issues]

Juergen Hoeller commented

This is a repackaged version of Objenesis (https://github.com/easymock/objenesis/releases) which includes a sun.misc.Unsafe based instantiator but only really uses it on Android and as a fallback on unknown JVMs. For well-known JVMs such as OpenJDK or the Oracle JDK, it uses a sun.reflect.ReflectionFactory based instantiator instead which is supported on JDK 9.

FWIW, according to the most recent conversations, sun.misc.Unsafe instead is also still supported on JDK 9 for the time being. Which version of jdep are you running there?

In Spring, we are using Objenesis to create side-effect free proxy instances with CGLIB (i.e. no constructor invocation side effects for proxy instances, just for target instances), and to not enforce default constructors on proxy classes to begin with. If this fails for any reason, we fall back to an invocation of the default constructor on the proxy class, so the use of Objenesis (and therefore the use of ReflectionFactory or Unsafe) is not actually mandatory.

[spring-projects-issues]

rajendra rathore commented

I saw the latest version of objenesis and they remove that file, so just want to check which version of objenesis we are using it.

[spring-projects-issues]

Juergen Hoeller commented

We're currently repackaging Objenesis 2.5.1 and will be upgrading to Objenesis 2.6 once released (#20159), probably in time for our 5.0 GA and 4.3.10 releases.

As far as I can see, UnsafeFactoryInstantiator is still around: https://github.com/easymock/objenesis/blob/master/main/src/main/java/org/objenesis/instantiator/sun/UnsafeFactoryInstantiator.java

Note that the jdeps tool just gives indications. Conditional use of Unsafe as a fallback code path on older / third-party JDKs does not matter as long as it's not being used on OpenJDK 9 and Oracle JDK 9. In fact, even on the latter, Unsafe remains effectively supported for the time being.