--- a/src/java.xml/share/classes/com/sun/org/apache/xml/internal/serializer/ToStream.java	Mon Jun 08 13:57:55 2020 +0200
+++ b/src/java.xml/share/classes/com/sun/org/apache/xml/internal/serializer/ToStream.java	Tue Jun 09 21:23:33 2020 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2020, Oracle and/or its affiliates. All rights reserved.
  */
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
@@ -51,7 +51,7 @@
  * serializers (xml, html, text ...) that write output to a stream.
  *
  * @xsl.usage internal
- * @LastModified: Aug 2019
+ * @LastModified: June 2020
  */
 abstract public class ToStream extends SerializerBase {
 
@@ -1354,7 +1354,7 @@
         // characters to read from array is 0.
         // Section 7.6.1 of XSLT 1.0 (http://www.w3.org/TR/xslt#value-of) suggest no text node
         // is created if string is empty.
-        if (length == 0 || (isInEntityRef()))
+        if (length == 0 || (isInEntityRef() && !m_expandDTDEntities))
             return;
 
         final boolean shouldNotFormat = !shouldFormatOutput();
@@ -1668,7 +1668,7 @@
      */
     public void characters(String s) throws org.xml.sax.SAXException
     {
-        if (isInEntityRef())
+        if (isInEntityRef() && !m_expandDTDEntities)
             return;
         final int length = s.length();
         if (length > m_charsBuff.length)
@@ -2514,7 +2514,7 @@
             m_inExternalDTD = true;
 
         // if this is not the magic [dtd] name
-        if (!m_inExternalDTD) {
+        if (!m_expandDTDEntities && !m_inExternalDTD) {
             // if it's not in nested entity reference
             if (!isInEntityRef()) {
                 if (shouldFormatOutput()) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jaxp/javax/xml/jaxp/unittest/transform/SAXFilterTest.java	Tue Jun 09 21:23:33 2020 +0000
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. 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.
+ */
+
+package transform;
+
+import java.io.StringReader;
+import java.io.StringWriter;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.parsers.SAXParser;
+import javax.xml.parsers.SAXParserFactory;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.sax.SAXSource;
+import javax.xml.transform.stream.StreamResult;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+import org.xml.sax.Attributes;
+import org.xml.sax.InputSource;
+import org.xml.sax.SAXException;
+import org.xml.sax.XMLFilter;
+import org.xml.sax.XMLReader;
+import org.xml.sax.helpers.XMLFilterImpl;
+
+/*
+ * @test
+ * @bug 8237456
+ * @modules java.xml
+ * @run testng transform.SAXFilterTest
+ * @summary Verifies that reference entities are not written out when the element
+ * is skipped through a filter.
+ */
+public class SAXFilterTest {
+
+    static final String XML = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+            + "<thing1 xmlns=\"things\">\n"
+            + "    <name>This &amp; That</name>\n"
+            + "    <thing2>\n"
+            + "        <name>The Other</name>\n"
+            + "    </thing2>\n"
+            + "    <thing2>\n"
+            + "        <name>Whatever</name>\n"
+            + "    </thing2>\n"
+            + "</thing1>";
+
+    static final String UNEXPECTED = "&amp;";
+
+    @Test
+    public void test() throws Exception {
+        Transformer t = TransformerFactory.newInstance().newTransformer();
+        XMLFilter filter = new Thing2Filter(getParser());
+        StringWriter sw = new StringWriter();
+        t.transform(new SAXSource(filter, new InputSource(new StringReader(XML))),
+                new StreamResult(sw));
+        Assert.assertFalse(sw.toString().contains(UNEXPECTED));
+        System.out.println(sw.toString());
+    }
+
+    private XMLReader getParser() {
+        XMLReader reader = null;
+        try {
+            SAXParserFactory factory = SAXParserFactory.newInstance();
+
+            String saxParserFactoryClassName = factory.getClass().getName();
+            System.out.println("SAXParserFactory class: " + saxParserFactoryClassName);
+
+            factory.setValidating(false);
+            factory.setNamespaceAware(true);
+
+            SAXParser parser = factory.newSAXParser();
+            reader = parser.getXMLReader();
+            System.out.println("XmlReader class: " + reader.getClass().getName());
+        } catch (ParserConfigurationException pce) {
+            pce.printStackTrace();
+        } catch (SAXException se) {
+            se.printStackTrace();
+        }
+        return reader;
+    }
+
+    class Thing2Filter extends XMLFilterImpl {
+
+        private boolean inMatch = false;
+        private int elementLocator;
+        private boolean doneMatching = false;
+
+        public Thing2Filter(XMLReader parent) {
+            super(parent);
+        }
+
+        @Override
+        public void startDocument() throws SAXException {
+            doneMatching = false;
+            super.startDocument();
+        }
+
+        @Override
+        public void startElement(String namespaceURI, String localName, String qName, Attributes attrs) throws SAXException {
+            if (localName.equals("thing2") && !doneMatching) { // start matching when the first thing2 is hit
+                inMatch = true;
+            }
+
+            if (inMatch) {
+                super.startElement(namespaceURI, localName, qName, attrs);
+            }
+        }
+
+        @Override
+        public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
+            if (inMatch) {
+                super.endElement(namespaceURI, localName, qName);
+            }
+            if (localName.equals("thing2")) { // match is over once end of first thing2 is hit
+                inMatch = false;
+                doneMatching = true;
+            }
+        }
+
+        @Override
+        public void characters(char[] ch, int start, int length) throws SAXException {
+            if (inMatch) {
+                super.characters(ch, start, length);
+            }
+        }
+
+        @Override
+        public void startPrefixMapping(java.lang.String prefix, java.lang.String uri) throws SAXException {
+            super.startPrefixMapping(prefix, uri);
+        }
+
+        @Override
+        public void endPrefixMapping(java.lang.String prefix) throws SAXException {
+            super.endPrefixMapping(prefix);
+        }
+    }
+}