From 2af4ae1b433cc55feaf648e86a897772ff9df08b Mon Sep 17 00:00:00 2001
From: Rui Li <ruiamzn@amazon.com>
Date: Tue, 14 Jan 2025 21:29:52 +0000
Subject: [PATCH] Backport 10d08dbc81aa14499410f0a7a64d0b3243b660f1

---
 .../impl/xpath/regex/RegularExpression.java   | 40 +++++++++++--------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/src/java.xml/share/classes/com/sun/org/apache/xerces/internal/impl/xpath/regex/RegularExpression.java b/src/java.xml/share/classes/com/sun/org/apache/xerces/internal/impl/xpath/regex/RegularExpression.java
index 7ca00f4ff7f..d8154f46ac6 100644
--- a/src/java.xml/share/classes/com/sun/org/apache/xerces/internal/impl/xpath/regex/RegularExpression.java
+++ b/src/java.xml/share/classes/com/sun/org/apache/xerces/internal/impl/xpath/regex/RegularExpression.java
@@ -704,11 +704,13 @@ public boolean matches(char[]  target, Match match) {
      */
     public boolean matches(char[] target, int start, int end, Match match) {
 
-        synchronized (this) {
-            if (this.operations == null)
-                this.prepare();
-            if (this.context == null)
-                this.context = new Context();
+        if (this.operations == null || this.context == null) {
+            synchronized (this) {
+                if (this.operations == null)
+                    this.prepare();
+                if (this.context == null)
+                    this.context = new Context();
+            }
         }
         Context con = null;
         synchronized (this.context) {
@@ -889,11 +891,13 @@ public boolean matches(String  target, Match match) {
      */
     public boolean matches(String  target, int start, int end, Match match) {
 
-        synchronized (this) {
-            if (this.operations == null)
-                this.prepare();
-            if (this.context == null)
-                this.context = new Context();
+        if (this.operations == null || this.context == null) {
+            synchronized (this) {
+                if (this.operations == null)
+                    this.prepare();
+                if (this.context == null)
+                    this.context = new Context();
+            }
         }
         Context con = null;
         synchronized (this.context) {
@@ -1569,11 +1573,13 @@ public boolean matches(CharacterIterator  target, Match match) {
 
 
 
-        synchronized (this) {
-            if (this.operations == null)
-                this.prepare();
-            if (this.context == null)
-                this.context = new Context();
+        if (this.operations == null || this.context == null) {
+            synchronized (this) {
+                if (this.operations == null)
+                    this.prepare();
+                if (this.context == null)
+                    this.context = new Context();
+            }
         }
         Context con = null;
         synchronized (this.context) {
@@ -1738,9 +1744,9 @@ else if (this.firstChar != null) {
     boolean hasBackReferences = false;
 
     transient int minlength;
-    transient Op operations = null;
+    transient volatile Op operations = null;
     transient int numberOfClosures;
-    transient Context context = null;
+    transient volatile Context context = null;
     transient RangeToken firstChar = null;
 
     transient String fixedString = null;