From 6b31ab01eaf234411503d781b42b7828d85a2cb6 Mon Sep 17 00:00:00 2001
From: Andriy Redko <drreta@gmail.com>
Date: Fri, 19 Jul 2024 17:18:09 -0400
Subject: [PATCH] CXF-9037: NPE when using
 com.ctc.wstx.returnNullForDefaultNamespace=true (#1962)

* CXF-9037: NPE when using com.ctc.wstx.returnNullForDefaultNamespace=true

* Address code review comments
---
 .../org/apache/cxf/staxutils/StaxSource.java  |  5 +++
 .../apache/cxf/staxutils/StaxUtilsTest.java   | 37 +++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/core/src/main/java/org/apache/cxf/staxutils/StaxSource.java b/core/src/main/java/org/apache/cxf/staxutils/StaxSource.java
index f74058406d8..2416d5596b9 100644
--- a/core/src/main/java/org/apache/cxf/staxutils/StaxSource.java
+++ b/core/src/main/java/org/apache/cxf/staxutils/StaxSource.java
@@ -142,6 +142,11 @@ protected void parse() throws SAXException {
                         if (nsUri == null) {
                             nsUri = "";
                         }
+                        // see please "com.ctc.wstx.returnNullForDefaultNamespace" property
+                        if (nsPrefix == null) {
+                            nsPrefix = "";
+                        }
+
                         contentHandler.startPrefixMapping(nsPrefix, nsUri);
                     }
                     contentHandler.startElement(uri == null ? "" : uri, localName, qname, getAttributes());
diff --git a/core/src/test/java/org/apache/cxf/staxutils/StaxUtilsTest.java b/core/src/test/java/org/apache/cxf/staxutils/StaxUtilsTest.java
index 1e97337c754..d2272da7b4d 100644
--- a/core/src/test/java/org/apache/cxf/staxutils/StaxUtilsTest.java
+++ b/core/src/test/java/org/apache/cxf/staxutils/StaxUtilsTest.java
@@ -25,6 +25,7 @@
 import java.io.StringReader;
 import java.io.StringWriter;
 import java.io.Writer;
+import java.nio.charset.StandardCharsets;
 
 import javax.xml.namespace.QName;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -47,11 +48,14 @@
 
 import org.xml.sax.InputSource;
 
+import com.ctc.wstx.stax.WstxInputFactory;
+
 import org.apache.cxf.helpers.DOMUtils;
 import org.apache.cxf.helpers.IOUtils;
 
 import org.junit.Test;
 
+import static org.hamcrest.CoreMatchers.startsWith;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.core.IsEqual.equalTo;
 import static org.junit.Assert.assertEquals;
@@ -242,6 +246,39 @@ public void testEmptyNamespace() throws Exception {
         cycleString(testString);
     }
 
+    
+    @Test
+    public void testNullForDefaultNamespace() throws Exception {
+        final String bodyXml = "<?xml version=\"1.0\"?>\n"
+            + "<soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">\n"
+            + "  <soap:Body>\n"
+            + "    <testReq xmlns=\"http://test.com/test\">\n"
+            + "        <reqBody>&lt;&lt;&lt;&lt;&lt;</reqBody>\n"
+            + "    </testReq>\n"
+            + "  </soap:Body>\n"
+            + "</soap:Envelope>\n";
+
+        try (ByteArrayInputStream in = new ByteArrayInputStream(bodyXml.getBytes(StandardCharsets.UTF_8))) {
+            final WstxInputFactory factory = new WstxInputFactory();
+            factory.setProperty("com.ctc.wstx.returnNullForDefaultNamespace", "true");
+
+            final Source beforeSource = new StaxSource(factory.createXMLStreamReader(in));
+            StringWriter writer = new StringWriter();
+            StreamResult result = new StreamResult(writer);
+    
+            TransformerFactory tf = TransformerFactory.newInstance();
+    
+            Transformer transformer = tf.newTransformer();
+            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
+            transformer.setOutputProperty(OutputKeys.STANDALONE, "yes");
+            transformer.setOutputProperty(OutputKeys.CDATA_SECTION_ELEMENTS, "Q{http://test.com/test}reqBody");
+            transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
+    
+            transformer.transform(beforeSource, result);
+            assertThat(writer.toString(), startsWith("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>"));
+        }
+    }
+
     private void cycleString(String s) throws Exception {
         StringReader reader = new StringReader(s);
         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();