From: Yoshito Umaoka <y.umaoka@gmail.com>
Date: Wed, 15 Mar 2017 01:27:58 +0000 (+0000)
Subject: ICU-12562 Applied the fix equivalent to the android patch to resolve TimeZone#getDefa... 
X-Git-Tag: release-59-rc~105
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=76d9f7e502afdbc7ab6f66318ddb756058fcb36a;p=icu

ICU-12562 Applied the fix equivalent to the android patch to resolve TimeZone#getDefault() threading issue.

X-SVN-Rev: 39809
---

diff --git a/icu4j/main/classes/core/src/com/ibm/icu/util/TimeZone.java b/icu4j/main/classes/core/src/com/ibm/icu/util/TimeZone.java
index 02c05a097d5..c10d3ffd8b0 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/util/TimeZone.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/util/TimeZone.java
@@ -927,19 +927,28 @@ abstract public class TimeZone implements Serializable, Cloneable, Freezable<Tim
      * @stable ICU 2.0
      */
     public static TimeZone getDefault() {
-        if (defaultZone == null) {
-            synchronized(TimeZone.class) {
-                if (defaultZone == null) {
-                    if (TZ_IMPL == TIMEZONE_JDK) {
-                        defaultZone = new JavaTimeZone();
-                    } else {
-                        java.util.TimeZone temp = java.util.TimeZone.getDefault();
-                        defaultZone = getFrozenTimeZone(temp.getID());
+        // Copy the reference to the current defaultZone,
+        // so it won't be affected by setDefault().
+        TimeZone tmpDefaultZone = defaultZone;
+
+        if (tmpDefaultZone == null) {
+            synchronized (java.util.TimeZone.class) {
+                synchronized(TimeZone.class) {
+                    tmpDefaultZone = defaultZone;
+                    if (tmpDefaultZone == null) {
+                        if (TZ_IMPL == TIMEZONE_JDK) {
+                            tmpDefaultZone = new JavaTimeZone();
+                        } else {
+                            java.util.TimeZone temp = java.util.TimeZone.getDefault();
+                            tmpDefaultZone = getFrozenTimeZone(temp.getID());
+                        }
+                        defaultZone = tmpDefaultZone;
                     }
                 }
             }
         }
-        return defaultZone.cloneAsThawed();
+
+        return tmpDefaultZone.cloneAsThawed();
     }
 
     /**