From e4d4fcf0300d40ca3a2062eee63f9b03279483ef Mon Sep 17 00:00:00 2001
From: Yuri Nesterenko <yan@openjdk.org>
Date: Fri, 8 Apr 2022 14:06:47 +0200
Subject: [PATCH] 8284548: Invalid XPath expression causes
 StringIndexOutOfBoundsException

Reviewed-by: bae
Backport-of: e58378a58e91bd10fc60031148b558230d43686f
---
 .../apache/xpath/internal/compiler/Lexer.java |  3 +-
 .../javax/xml/jaxp/XPath/InvalidXPath.java    | 53 +++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 jdk/test/javax/xml/jaxp/XPath/InvalidXPath.java

diff --git a/jaxp/src/com/sun/org/apache/xpath/internal/compiler/Lexer.java b/jaxp/src/com/sun/org/apache/xpath/internal/compiler/Lexer.java
index fa42d1a4a6..5c3e64d3ac 100644
--- a/jaxp/src/com/sun/org/apache/xpath/internal/compiler/Lexer.java
+++ b/jaxp/src/com/sun/org/apache/xpath/internal/compiler/Lexer.java
@@ -27,7 +27,6 @@ import java.util.Vector;
 import com.sun.org.apache.xalan.internal.res.XSLMessages;
 import com.sun.org.apache.xml.internal.utils.PrefixResolver;
 import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
-import java.util.Objects;
 import javax.xml.transform.TransformerException;
 import jdk.xml.internal.XMLSecurityManager;
 import jdk.xml.internal.XMLSecurityManager.Limit;
@@ -450,7 +449,7 @@ class Lexer
    * @return the next char
    */
   private char peekNext(String s, int index) {
-      if (index >= 0 && s.length() > index) {
+      if (index >= 0 && index < s.length() - 1) {
           return s.charAt(index + 1);
       }
       return 0;
diff --git a/jdk/test/javax/xml/jaxp/XPath/InvalidXPath.java b/jdk/test/javax/xml/jaxp/XPath/InvalidXPath.java
new file mode 100644
index 0000000000..478f4212d5
--- /dev/null
+++ b/jdk/test/javax/xml/jaxp/XPath/InvalidXPath.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022, SAP SE. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8284548
+ * @summary Test whether the expected exception is thrown when
+ *           trying to compile an invalid XPath expression.
+ * @run main InvalidXPath
+ */
+
+import javax.xml.xpath.XPathExpressionException;
+import javax.xml.xpath.XPathFactory;
+
+public class InvalidXPath {
+
+    public static void main(String... args) {
+        // define an invalid XPath expression
+        final String invalidXPath = ">>";
+
+        // expect XPathExpressionException when the invalid XPath expression is compiled
+        try {
+            XPathFactory.newInstance().newXPath().compile(invalidXPath);
+        } catch (XPathExpressionException e) {
+            System.out.println("Caught expected exception: " + e.getClass().getName() +
+                    "(" + e.getMessage() + ").");
+        } catch (Exception e) {
+            System.out.println("Caught unexpected exception: " + e.getClass().getName() +
+                    "(" + e.getMessage() + ")!");
+            throw e;
+        }
+    }
+}