RFR [9] CleanerImpl should not depend on ManagedLocalsThread

[Chris Hegarty]

With the addition of a Thread constructor that can suppress the inheriting
of inheritable thread-local variable initial values from the constructing
thread [1], the usages of ManagedLocalsThread were removed from
the base module.  ManagedLocalsThread was also removed from the 
hierarchy of InnocuousThread, to help reduce dependencies. As a
result InnocuousThread is no longer a ManagedLocalsThread, and 
the CleanerImpl should not use it in its instanceof check.

This just appears to be a timing issue as both changes were in flight.
I did not add an explicit test as this is implementation detail, but adding
one would be straight forward.  Such a test may be more appropriate
when 8146028 "Common Cleaner for finalization replacements in
java.base" [2], is added.


diff --git a/src/java.base/share/classes/jdk/internal/misc/CleanerImpl.java b/src/java.base/share/classes/jdk/internal/misc/CleanerImpl.java
--- a/src/java.base/share/classes/jdk/internal/misc/CleanerImpl.java
+++ b/src/java.base/share/classes/jdk/internal/misc/CleanerImpl.java
@@ -39,7 +39,6 @@
 import java.util.function.Function;
 
 import sun.misc.InnocuousThread;
-import sun.misc.ManagedLocalsThread;
 
 /**
  * CleanerImpl manages a set of object references and corresponding cleaning actions.
@@ -130,8 +129,8 @@
      */
     public void run() {
         Thread t = Thread.currentThread();
-        ManagedLocalsThread mlThread = (t instanceof ManagedLocalsThread)
-                ? (ManagedLocalsThread) t
+        InnocuousThread mlThread = (t instanceof InnocuousThread)
+                ? (InnocuousThread) t
                 : null;
         while (!phantomCleanableList.isListEmpty() ||
                 !weakCleanableList.isListEmpty() ||


-Chris.

[1] https://bugs.openjdk.java.net/browse/JDK-8056152
[2] https://bugs.openjdk.java.net/browse/JDK-8146028