Error in TestReleaseDirectMemory

Testing 3.3.1 release candidate, although it isn’t a regression. I encounter the same issues on 3.2.4-stable.

When running this example with JDK8:

Apr 21, 2020 10:09:02 AM com.jme3.system.JmeDesktopSystem initialize
INFO: Running on jMonkeyEngine 3.3.0-SNAPSHOT
 * Branch: v3.3
 * Git Hash: a150deb
 * Build Date: 2020-04-21
Apr 21, 2020 10:09:02 AM com.jme3.system.lwjgl.LwjglContext printContextInitInfo
INFO: LWJGL 2.9.3 context running on thread jME3 Main
 * Graphics Adapter: null
 * Driver Version: null
 * Scaling Factor: 1
Apr 21, 2020 10:09:02 AM com.jme3.app.LegacyApplication handleError
SEVERE: Uncaught exception thrown in Thread[jME3 Main,5,main]
java.lang.NoSuchMethodError: java.nio.IntBuffer.clear()Ljava/nio/IntBuffer;
	at com.jme3.util.BufferUtils.createIntBuffer(BufferUtils.java:927)
	at com.jme3.renderer.lwjgl.LwjglGL.<init>(LwjglGL.java:15)
	at com.jme3.system.lwjgl.LwjglContext.initContextFirstTime(LwjglContext.java:257)
	at com.jme3.system.lwjgl.LwjglContext.internalCreate(LwjglContext.java:424)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.initInThread(LwjglAbstractDisplay.java:117)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:213)
	at java.lang.Thread.run(Thread.java:748)
Exception: java.lang.NullPointerException thrown from the UncaughtExceptionHandler in thread "jME3 Main"

When running on JDK11:

Apr 21, 2020 10:10:38 AM com.jme3.system.JmeDesktopSystem initialize
INFO: Running on jMonkeyEngine 3.3.0-SNAPSHOT
 * Branch: v3.3
 * Git Hash: a150deb
 * Build Date: 2020-04-21
Apr 21, 2020 10:10:38 AM com.jme3.system.lwjgl.LwjglContext printContextInitInfo
INFO: LWJGL 2.9.3 context running on thread jME3 Main
 * Graphics Adapter: null
 * Driver Version: null
 * Scaling Factor: 1
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.jme3.util.ReflectionAllocator (file:/Users/remy/Projects/jMonkeyEngine/jmonkeyengine/jme3-core/build/libs/jme3-core-3.3.0-SNAPSHOT.jar) to method sun.nio.ch.DirectBuffer.cleaner()
WARNING: Please consider reporting this to the maintainers of com.jme3.util.ReflectionAllocator
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Apr 21, 2020 10:10:38 AM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: ATI Technologies Inc.
 * Renderer: AMD Radeon Pro Vega 20 OpenGL Engine
 * OpenGL Version: 2.1 ATI-2.11.21
 * GLSL Version: 1.20
 * Profile: Compatibility
Apr 21, 2020 10:10:39 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio Renderer Information
 * Device: MacBook Pro Speakers
 * Vendor: Apple Computer Inc.
 * Renderer: Software
 * Version: 1.1
 * Supported channels: 64
 * ALC extensions: ALC_EXT_CAPTURE ALC_ENUMERATION_EXT ALC_EXT_MAC_OSX ALC_EXT_ASA ALC_EXT_ASA_DISTORTION ALC_EXT_ASA_ROGER_BEEP
 * AL extensions: AL_EXT_OFFSET AL_EXT_LINEAR_DISTANCE AL_EXT_EXPONENT_DISTANCE AL_EXT_float32 AL_EXT_STATIC_BUFFER AL_EXT_SOURCE_NOTIFICATIONS AL_EXT_SOURCE_SPATIALIZATION
Apr 21, 2020 10:10:39 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
WARNING: Pausing audio device not supported.
Apr 21, 2020 10:10:39 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
WARNING: OpenAL EFX not available! Audio effects won't work.
Apr 21, 2020 10:10:39 AM com.jme3.util.ReflectionAllocator destroyDirectBuffer
SEVERE: Buffer cannot be destroyed: java.nio.DirectByteBuffer[pos=0 lim=500000 cap=500000]
Apr 21, 2020 10:10:39 AM com.jme3.util.ReflectionAllocator destroyDirectBuffer

[Ali-RS]

I could trace down the reason for

SEVERE: Buffer cannot be destroyed: java.nio.DirectByteBuffer[pos=0 lim=500000 cap=500000]

It appears that in Java 11+ the ReflectionAllocator stuck here and return null

https://github.com/jMonkeyEngine/jmonkeyengine/blob/8aa50e9b485a8e847fe90186caaee0ae4fd9963a/jme3-core/src/main/java/com/jme3/util/ReflectionAllocator.java#L84-L85

and can not clear the buffer

https://github.com/jMonkeyEngine/jmonkeyengine/blob/8aa50e9b485a8e847fe90186caaee0ae4fd9963a/jme3-core/src/main/java/com/jme3/util/ReflectionAllocator.java#L130-L132

to solve it you have to explicitly enable the base module by adding "--add-opens=java.base/jdk.internal.ref=ALL-UNNAMED"

–add-opens

If you have to allow code on the class path to do deep reflection to access nonpublic members, then use the --add-opens runtime option.

Some libraries do deep reflection, meaning setAccessible(true), so they can access all members, including private ones. You can grant this access using the --add-opens option on the java command line. No warning messages are generated as a result of using this option.

Please see below links for more info:

https://docs.oracle.com/en/java/javase/11/migrate/index.html#JSMIG-GUID-12F945EB-71D6-46AF-8C3D-D354FD0B1781

https://github.com/uncomplicate/neanderthal/issues/55

[Ali-RS]

Just a note for anyone who might come across this.

ReflectionAllocator seems to be broken (Buffer cannot be destroyed error) again with JDK 16, even using the workaround does not work anymore.