deprecate remaining classes of shared XML (#171)

diff --git a/src/main/java/org/apache/maven/shared/utils/xml/PrettyPrintXMLWriter.java b/src/main/java/org/apache/maven/shared/utils/xml/PrettyPrintXMLWriter.java
index 7f3838d..7c6ba77 100644
--- a/src/main/java/org/apache/maven/shared/utils/xml/PrettyPrintXMLWriter.java
+++ b/src/main/java/org/apache/maven/shared/utils/xml/PrettyPrintXMLWriter.java
@@ -26,8 +26,11 @@
 /**
  * XMLWriter with nice indentation.
  *
+ * @deprecated this class swallows and ignores IOExceptions. It is dangerous to use when writing
+ *    to anything other than a StringWriter.
  * @author kama
  */
+@Deprecated
 public class PrettyPrintXMLWriter implements XMLWriter {
     private static final char[] CLOSE_1 = "/>".toCharArray();
 
@@ -158,6 +161,7 @@
     }
 
     /** {@inheritDoc} */
+    @Override
     public void addAttribute(String key, String value) throws IOException {
         if (!processingElement) {
             throw new IllegalStateException("currently processing no element");
@@ -173,6 +177,7 @@
     }
 
     /** {@inheritDoc} */
+    @Override
     public void setEncoding(String encoding) {
         if (documentStarted) {
             throw new IllegalStateException("Document headers already written!");
@@ -182,6 +187,7 @@
     }
 
     /** {@inheritDoc} */
+    @Override
     public void setDocType(String docType) {
         if (documentStarted) {
             throw new IllegalStateException("Document headers already written!");
@@ -213,6 +219,7 @@
     }
 
     /** {@inheritDoc} */
+    @Override
     public void startElement(String elementName) throws IOException {
 
         if (elementName.isEmpty()) {
@@ -239,6 +246,7 @@
     }
 
     /** {@inheritDoc} */
+    @Override
     public void writeText(String text) throws IOException {
         ensureDocumentStarted();
 
@@ -254,6 +262,7 @@
     }
 
     /** {@inheritDoc} */
+    @Override
     public void writeMarkup(String markup) throws IOException {
         ensureDocumentStarted();
 
@@ -267,6 +276,7 @@
     }
 
     /** {@inheritDoc} */
+    @Override
     public void endElement() throws IOException {
         String chars = elementStack.get(--depth);
         if (processingElement) {
diff --git a/src/main/java/org/apache/maven/shared/utils/xml/XMLWriter.java b/src/main/java/org/apache/maven/shared/utils/xml/XMLWriter.java
index 83ee0ab..19a1901 100644
--- a/src/main/java/org/apache/maven/shared/utils/xml/XMLWriter.java
+++ b/src/main/java/org/apache/maven/shared/utils/xml/XMLWriter.java
@@ -24,6 +24,7 @@
  * Interface for tools writing XML files.
  * XMLWriters are not thread safe and must not be accessed concurrently.
  */
+@Deprecated
 public interface XMLWriter {
 
     /**
diff --git a/src/main/java/org/apache/maven/shared/utils/xml/XmlWriterUtil.java b/src/main/java/org/apache/maven/shared/utils/xml/XmlWriterUtil.java
index e2d14de..e321772 100644
--- a/src/main/java/org/apache/maven/shared/utils/xml/XmlWriterUtil.java
+++ b/src/main/java/org/apache/maven/shared/utils/xml/XmlWriterUtil.java
@@ -28,6 +28,7 @@
  * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
  *
  */
+@Deprecated
 public class XmlWriterUtil {
     /** The vm line separator */
     public static final String LS = System.getProperty("line.separator");