From 1ae617207543d079b95384bc2a57996392d5df09 Mon Sep 17 00:00:00 2001
Date: Fri, 22 Jan 2021 11:30:40 +0800
Subject: Backport of JDK-8157570

summary: sun.rmi.transport.GC retains a strong reference to the context class loader
LLT:
Bug url: https://bugs.openjdk.java.net/browse/JDK-8157570
---
 jdk/src/share/classes/sun/misc/GC.java | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/jdk/src/share/classes/sun/misc/GC.java b/jdk/src/share/classes/sun/misc/GC.java
index c77bf1d05..eb92617c1 100644
--- a/jdk/src/share/classes/sun/misc/GC.java
+++ b/jdk/src/share/classes/sun/misc/GC.java
@@ -29,6 +29,7 @@ import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.SortedSet;
 import java.util.TreeSet;
+import sun.misc.InnocuousThread;
 
 
 /**
@@ -83,8 +84,9 @@ public class GC {
     public static native long maxObjectInspectionAge();
 
 
-    private static class Daemon extends Thread {
+    private static class Daemon implements Runnable {
 
+        @Override
         public void run() {
             for (;;) {
                 long l;
@@ -122,23 +124,17 @@ public class GC {
             }
         }
 
-        private Daemon(ThreadGroup tg) {
-            super(tg, "GC Daemon");
-        }
-
-        /* Create a new daemon thread in the root thread group */
+        /* Create a new daemon thread */
         public static void create() {
             PrivilegedAction<Void> pa = new PrivilegedAction<Void>() {
                 public Void run() {
-                    ThreadGroup tg = Thread.currentThread().getThreadGroup();
-                    for (ThreadGroup tgn = tg;
-                         tgn != null;
-                         tg = tgn, tgn = tg.getParent());
-                    Daemon d = new Daemon(tg);
-                    d.setDaemon(true);
-                    d.setPriority(Thread.MIN_PRIORITY + 1);
-                    d.start();
-                    GC.daemon = d;
+                    Thread t = InnocuousThread.newSystemThread("RMI GC Daemon",
+                                                               new Daemon());
+                    assert t.getContextClassLoader() == null;
+                    t.setDaemon(true);
+                    t.setPriority(Thread.MIN_PRIORITY + 1);
+                    t.start();
+                    GC.daemon = t;
                     return null;
                 }};
             AccessController.doPrivileged(pa);
-- 
2.19.0