[core] Refactor XMLRenderer to use XMLStreamWriter

In order to properly support different encodings, a OutputStream
is needed. Then Java will take care of unmappaple characters
and encode them as entities for XML.

For backwards compatibility, a writer is still created and exposed.

pmd-core/src/main/java/net/sourceforge/pmd/renderers/XSLTRenderer.java

@@ -45,6 +45,7 @@ public class XSLTRenderer extends XMLRenderer {
     private Transformer transformer;
     private String xsltFilename = "/pmd-nicerhtml.xsl";
     private Writer outputWriter;
+    private StringWriter stringWriter;
 
     public XSLTRenderer() {
         super();
@@ -71,8 +72,8 @@ public class XSLTRenderer extends XMLRenderer {
         // We keep the inital writer to put the final html output
         this.outputWriter = getWriter();
         // We use a new one to store the XML...
-        Writer w = new StringWriter();
-        setWriter(w);
+        this.stringWriter = new StringWriter();
+        setWriter(stringWriter);
         // If don't find the xsl no need to bother doing the all report,
         // so we check this here...
         InputStream xslt = null;
@@ -100,16 +101,14 @@ public class XSLTRenderer extends XMLRenderer {
      *            The stylesheet provided as an InputStream
      */
     private void prepareTransformer(InputStream xslt) {
-        if (xslt != null) {
-            try {
-                // Get a TransformerFactory object
-                TransformerFactory factory = TransformerFactory.newInstance();
-                StreamSource src = new StreamSource(xslt);
-                // Get an XSL Transformer object
-                this.transformer = factory.newTransformer(src);
-            } catch (TransformerConfigurationException e) {
-                e.printStackTrace();
-            }
+        try {
+            // Get a TransformerFactory object
+            TransformerFactory factory = TransformerFactory.newInstance();
+            StreamSource src = new StreamSource(xslt);
+            // Get an XSL Transformer object
+            this.transformer = factory.newTransformer(src);
+        } catch (TransformerConfigurationException e) {
+            throw new RuntimeException(e);
         }
     }
 
@@ -118,25 +117,17 @@ public class XSLTRenderer extends XMLRenderer {
         // First we finish the XML report
         super.end();
         // Now we transform it using XSLT
-        if (writer instanceof StringWriter) {
-            StringWriter w = (StringWriter) writer;
-            Document doc = this.getDocument(w.toString());
-            this.transform(doc);
-        } else {
-            // Should not happen !
-            throw new RuntimeException("Wrong writer");
-        }
-
+        Document doc = this.getDocument(stringWriter.toString());
+        this.transform(doc);
     }
 
     private void transform(Document doc) {
         DOMSource source = new DOMSource(doc);
-        this.setWriter(new StringWriter());
         StreamResult result = new StreamResult(this.outputWriter);
         try {
             transformer.transform(source, result);
         } catch (TransformerException e) {
-            e.printStackTrace();
+            throw new RuntimeException(e);
         }
     }
 
@@ -145,8 +136,7 @@ public class XSLTRenderer extends XMLRenderer {
             DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
             return parser.parse(new InputSource(new StringReader(xml)));
         } catch (ParserConfigurationException | SAXException | IOException e) {
-            e.printStackTrace();
+            throw new RuntimeException(e);
         }
-        return null;
     }
 }

pmd-core/src/test/java/net/sourceforge/pmd/renderers/XMLRendererTest.java

@@ -125,10 +125,10 @@ public class XMLRendererTest extends AbstractRendererTest {
 
     public String getHeader() {
         return "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + PMD.EOL
-                + "<pmd xmlns=\"http://pmd.sourceforge.net/report/2.0.0\"" + PMD.EOL
-                + "    xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"" + PMD.EOL
-                + "    xsi:schemaLocation=\"http://pmd.sourceforge.net/report/2.0.0 http://pmd.sourceforge.net/report_2_0_0.xsd\"" + PMD.EOL
-                + "    version=\"" + PMDVersion.VERSION + "\" timestamp=\"2014-10-06T19:30:51.262\">" + PMD.EOL;
+                + "<pmd xmlns=\"http://pmd.sourceforge.net/report/2.0.0\""
+                + " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\""
+                + " xsi:schemaLocation=\"http://pmd.sourceforge.net/report/2.0.0 http://pmd.sourceforge.net/report_2_0_0.xsd\""
+                + " version=\"" + PMDVersion.VERSION + "\" timestamp=\"2014-10-06T19:30:51.262\">" + PMD.EOL;
     }
 
     @Test

pmd-java/src/test/java/net/sourceforge/pmd/ant/PMDTaskTest.java

@@ -8,10 +8,8 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.io.UnsupportedEncodingException;
-import java.lang.reflect.Field;
 import java.nio.charset.Charset;
 import java.util.Locale;
-import java.util.Objects;
 
 import org.apache.commons.io.FileUtils;
 import org.junit.Rule;
@@ -112,17 +110,8 @@ public class PMDTaskTest extends AbstractAntTestHelper {
         }
     };
 
-    // See http://stackoverflow.com/questions/361975/setting-the-default-java-character-encoding and http://stackoverflow.com/a/14987992/1169968
     private static void setDefaultCharset(String charsetName) {
-        try {
-            System.setProperty("file.encoding", charsetName);
-            Field charset = Charset.class.getDeclaredField("defaultCharset");
-            charset.setAccessible(true);
-            charset.set(null, null);
-            Objects.requireNonNull(Charset.defaultCharset());
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        }
+        System.setProperty("file.encoding", charsetName);
     }
 
     @Rule