diff --git a/spring-web/src/main/java/org/springframework/http/converter/xml/SourceHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/xml/SourceHttpMessageConverter.java
index 3b9fe81938..e970450cf3 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/xml/SourceHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/xml/SourceHttpMessageConverter.java
@@ -20,7 +20,8 @@ import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-
+import java.util.HashSet;
+import java.util.Set;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
@@ -42,6 +43,7 @@ import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
 import org.xml.sax.XMLReader;
 import org.xml.sax.helpers.XMLReaderFactory;
+
 import org.springframework.http.HttpInputMessage;
 import org.springframework.http.HttpOutputMessage;
 import org.springframework.http.MediaType;
@@ -60,10 +62,22 @@ import org.springframework.util.StreamUtils;
  */
 public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMessageConverter<T> {
 
+	private static final Set<Class<?>> SUPPORTED_CLASSES = new HashSet<Class<?>>(5);
+
+	static {
+		SUPPORTED_CLASSES.add(DOMSource.class);
+		SUPPORTED_CLASSES.add(SAXSource.class);
+		SUPPORTED_CLASSES.add(StAXSource.class);
+		SUPPORTED_CLASSES.add(StreamSource.class);
+		SUPPORTED_CLASSES.add(Source.class);
+	}
+
+
 	private final TransformerFactory transformerFactory = TransformerFactory.newInstance();
 
 	private boolean processExternalEntities = false;
 
+
 	/**
 	 * Sets the {@link #setSupportedMediaTypes(java.util.List) supportedMediaTypes}
 	 * to {@code text/xml} and {@code application/xml}, and {@code application/*-xml}.
@@ -74,18 +88,17 @@ public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMe
 
 
 	/**
-	 * Indicates whether external XML entities are processed when converting
-	 * to a Source.
+	 * Indicates whether external XML entities are processed when converting to a Source.
 	 * <p>Default is {@code false}, meaning that external entities are not resolved.
 	 */
 	public void setProcessExternalEntities(boolean processExternalEntities) {
 		this.processExternalEntities = processExternalEntities;
 	}
 
+
 	@Override
 	public boolean supports(Class<?> clazz) {
-		return DOMSource.class.equals(clazz) || SAXSource.class.equals(clazz)
-				|| StreamSource.class.equals(clazz) || Source.class.equals(clazz);
+		return SUPPORTED_CLASSES.contains(clazz);
 	}
 
 	@Override
@@ -108,7 +121,7 @@ public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMe
 		}
 		else {
 			throw new HttpMessageConversionException("Could not read class [" + clazz +
-					"]. Only DOMSource, SAXSource, and StreamSource are supported.");
+					"]. Only DOMSource, SAXSource, StAXSource, and StreamSource are supported.");
 		}
 	}
 
@@ -116,7 +129,8 @@ public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMe
 		try {
 			DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
 			documentBuilderFactory.setNamespaceAware(true);
-			documentBuilderFactory.setFeature("http://xml.org/sax/features/external-general-entities", processExternalEntities);
+			documentBuilderFactory.setFeature(
+					"http://xml.org/sax/features/external-general-entities", this.processExternalEntities);
 			DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
 			Document document = documentBuilder.parse(body);
 			return new DOMSource(document);
@@ -132,7 +146,8 @@ public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMe
 	private SAXSource readSAXSource(InputStream body) throws IOException {
 		try {
 			XMLReader reader = XMLReaderFactory.createXMLReader();
-			reader.setFeature("http://xml.org/sax/features/external-general-entities", processExternalEntities);
+			reader.setFeature(
+					"http://xml.org/sax/features/external-general-entities", this.processExternalEntities);
 			byte[] bytes = StreamUtils.copyToByteArray(body);
 			return new SAXSource(reader, new InputSource(new ByteArrayInputStream(bytes)));
 		}
@@ -144,7 +159,8 @@ public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMe
 	private Source readStAXSource(InputStream body) {
 		try {
 			XMLInputFactory inputFactory = XMLInputFactory.newFactory();
-			inputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", processExternalEntities);
+			inputFactory.setProperty(
+					"javax.xml.stream.isSupportingExternalEntities", this.processExternalEntities);
 			XMLStreamReader streamReader = inputFactory.createXMLStreamReader(body);
 			return new StAXSource(streamReader);
 		}
@@ -192,21 +208,21 @@ public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMe
 
 	private static class CountingOutputStream extends OutputStream {
 
-		private long count = 0;
+		long count = 0;
 
 		@Override
 		public void write(int b) throws IOException {
-			count++;
+			this.count++;
 		}
 
 		@Override
 		public void write(byte[] b) throws IOException {
-			count += b.length;
+			this.count += b.length;
 		}
 
 		@Override
 		public void write(byte[] b, int off, int len) throws IOException {
-			count += len;
+			this.count += len;
 		}
 	}