From 21b1da1bea56e2b442c2e0c9a580547356268426 Mon Sep 17 00:00:00 2001
From: Jason Tedor <jason@tedor.me>
Date: Fri, 22 Apr 2016 08:05:33 -0400
Subject: [PATCH] Kill thread local leak

This commit modifies InjectorImpl to prevent a thread local leak in
certain web containers. This leak can arise when starting a node client
inside such a web container. The underlying issue is that the
ThreadLocal instance was created via an anonymous class. Such an
anonymous class has an implicit reference back to the InjectorImpl in
which it was created. The solution here is to not use an anonymous class
but instead just create the reference locally and set it on the thread
local.

Relates #17921
---
 .../elasticsearch/common/inject/InjectorImpl.java   | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/core/src/main/java/org/elasticsearch/common/inject/InjectorImpl.java b/core/src/main/java/org/elasticsearch/common/inject/InjectorImpl.java
index c8f80ef7fd6..ae4cd744dd0 100644
--- a/core/src/main/java/org/elasticsearch/common/inject/InjectorImpl.java
+++ b/core/src/main/java/org/elasticsearch/common/inject/InjectorImpl.java
@@ -84,12 +84,7 @@ class InjectorImpl implements Injector, Lookups {
         if (parent != null) {
             localContext = parent.localContext;
         } else {
-            localContext = new ThreadLocal<Object[]>() {
-                @Override
-                protected Object[] initialValue() {
-                    return new Object[1];
-                }
-            };
+            localContext = new ThreadLocal<>();
         }
     }
 
@@ -867,13 +862,17 @@ class InjectorImpl implements Injector, Lookups {
         return getProvider(type).get();
     }
 
-    final ThreadLocal<Object[]> localContext;
+    private final ThreadLocal<Object[]> localContext;
 
     /**
      * Looks up thread local context. Creates (and removes) a new context if necessary.
      */
     <T> T callInContext(ContextualCallable<T> callable) throws ErrorsException {
         Object[] reference = localContext.get();
+        if (reference == null) {
+            reference = new Object[1];
+            localContext.set(reference);
+        }
         if (reference[0] == null) {
             reference[0] = new InternalContext();
             try {