26 Java 9 Support

This is a list of known issues, caveats, and workarounds to use early Java 9+ support. While Java 9 support is far from complete, core functionality appears to work with only a few warnings and messages here and there.

1.26 Known Library Caveats

The following are known version conflicts or requirements for Ratpack to run seamlessly on Java 9.

• ratpack-groovy requires Groovy 2.5.2 or higher per issue #1411
• ratpack-groovy-test requires Groovy 2.5.2 or higher per issue #1411

2.26 Known Issues

The following are issues caused by Java 9 and the underlying components to Ratpack at this time. Workarounds will be provided in each case

3.26 Known Java 9 Errors/Warning messages

The following are messages emitted by Java 9+ that are expected.

• Guice illegal reflective access in issue google/guice#1133:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.google.inject.internal.cglib.core.$ReflectUtils$1 (file:[User Gradle Cache Directory]/modules-2/files-2.1/com.google.inject/guice/[version hash]/[guice version jar]]
WARNING: Please consider reporting this to the maintainers of com.google.inject.internal.cglib.core.$ReflectUtils$1
WARNING: Use –illegal-access=warn to enable warnings on further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

• Netty debug messages described in issue #1410:

11:04:44.477 [main] DEBUG i.n.u.i.PlatformDependent0 - -Dio.netty.noUnsafe: false
11:04:44.477 [main] DEBUG i.n.u.i.PlatformDependent0 - Java version: 11
11:04:44.479 [main] DEBUG i.n.u.i.PlatformDependent0 - sun.misc.Unsafe.theUnsafe: available
11:04:44.479 [main] DEBUG i.n.u.i.PlatformDependent0 - sun.misc.Unsafe.copyMemory: available
11:04:44.480 [main] DEBUG i.n.u.i.PlatformDependent0 - java.nio.Buffer.address: available
11:04:44.483 [main] DEBUG i.n.u.i.PlatformDependent0 - direct buffer constructor: unavailable
java.lang.UnsupportedOperationException: Reflective setAccessible(true) disabled
at io.netty.util.internal.ReflectionUtil.trySetAccessible(ReflectionUtil.java:31)
at io.netty.util.internal.PlatformDependent0$4.run(PlatformDependent0.java:224)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at io.netty.util.internal.PlatformDependent0.(PlatformDependent0.java:218)
at io.netty.util.internal.PlatformDependent.isAndroid(PlatformDependent.java:212)
at io.netty.util.internal.PlatformDependent.(PlatformDependent.java:80)
at io.netty.util.ConstantPool.(ConstantPool.java:32)
at io.netty.util.AttributeKey$1.(AttributeKey.java:27)
at io.netty.util.AttributeKey.(AttributeKey.java:27)
at ratpack.core.server.internal.DefaultRatpackServer.(DefaultRatpackServer.java:69)
at ratpack.core.server.RatpackServer.of(RatpackServer.java:81)
at ratpack.core.server.RatpackServer.start(RatpackServer.java:92)
at ratpack.groovy.GroovyRatpackMain.main(GroovyRatpackMain.java:38)
11:04:44.484 [main] DEBUG i.n.u.i.PlatformDependent0 - java.nio.Bits.unaligned: available, true
11:04:44.485 [main] DEBUG i.n.u.i.PlatformDependent0 - jdk.internal.misc.Unsafe.allocateUninitializedArray(int): unavailable
java.lang.IllegalAccessException: class io.netty.util.internal.PlatformDependent0$6 cannot access class jdk.internal.misc.Unsafe (in module java.base) because module java.base does not export jdk.internal.misc to unnamed module @366647c2
at java.base/jdk.internal.reflect.Reflection.newIllegalAccessException(Reflection.java:361)
at java.base/java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:591)
at java.base/java.lang.reflect.Method.invoke(Method.java:558)
at io.netty.util.internal.PlatformDependent0$6.run(PlatformDependent0.java:334)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at io.netty.util.internal.PlatformDependent0.(PlatformDependent0.java:325)
at io.netty.util.internal.PlatformDependent.isAndroid(PlatformDependent.java:212)
at io.netty.util.internal.PlatformDependent.(PlatformDependent.java:80)
at io.netty.util.ConstantPool.(ConstantPool.java:32)
at io.netty.util.AttributeKey$1.(AttributeKey.java:27)
at io.netty.util.AttributeKey.(AttributeKey.java:27)
at ratpack.core.server.internal.DefaultRatpackServer.(DefaultRatpackServer.java:69)
at ratpack.core.server.RatpackServer.of(RatpackServer.java:81)
at ratpack.core.server.RatpackServer.start(RatpackServer.java:92)
at ratpack.groovy.GroovyRatpackMain.main(GroovyRatpackMain.java:38)
11:04:44.485 [main] DEBUG i.n.u.i.PlatformDependent0 - java.nio.DirectByteBuffer.(long, int): unavailable
11:04:44.485 [main] DEBUG i.n.u.internal.PlatformDependent - sun.misc.Unsafe: available