fix some pmd warnings

Author: rbri

src/main/java/org/htmlunit/WebClient.java

@@ -2553,6 +2553,7 @@ private void readObject(final ObjectInputStream in) throws IOException, ClassNot
         scriptEngine_ = new JavaScriptEngine(this);
         jobManagers_ = Collections.synchronizedList(new ArrayList<>());
         loadQueue_ = new ArrayList<>();
+        css3ParserPool_ = new CSS3ParserPool();
     }
 
     private static class LoadJob {
@@ -2948,7 +2949,7 @@ static class CSS3ParserPool {
          * Our pool. We only hold data when it is available. In addition, synchronization against
          * this deque is cheap.
          */
-        private ConcurrentLinkedDeque<PooledCSS3Parser> parsers_ = new ConcurrentLinkedDeque<>();
+        private final ConcurrentLinkedDeque<PooledCSS3Parser> parsers_ = new ConcurrentLinkedDeque<>();
 
         /**
          * Fetch a new or recycled CSS3parser. Make sure you use the try-with-resource concept

src/main/java/org/htmlunit/html/DomNodeIterator.java

@@ -143,15 +143,7 @@ private DomNode traverse(final boolean next) {
             }
             else {
                 if (beforeNode) {
-                    final DomNode left = getSibling(node, true);
-                    if (left == null) {
-                        final Node parent = node.getParentNode();
-                        if (parent == null) {
-                            node = null;
-                        }
-                    }
-
-                    DomNode follow = left;
+                    DomNode follow = getSibling(node, true);
                     if (follow != null) {
                         while (follow.hasChildNodes()) {
                             final DomNode toFollow = getChild(follow, false);

src/main/java/org/htmlunit/html/HtmlPage.java

@@ -2874,7 +2874,7 @@ private void readObject(final ObjectInputStream in) throws IOException, ClassNot
     }
 
     private static final class MappedElementIndexEntry implements Serializable {
-        private ArrayList<DomElement> elements_;
+        private final ArrayList<DomElement> elements_;
         private boolean sorted_;
 
         MappedElementIndexEntry() {

src/main/java/org/htmlunit/javascript/host/Window.java

@@ -203,7 +203,7 @@ public class Window extends EventTarget implements WindowOrWorkerGlobalScope, Au
     private Map<Class<? extends Scriptable>, Scriptable> prototypes_ = new HashMap<>();
     private Object controllers_;
     private Object opener_;
-    private Object top_ = NOT_FOUND; // top can be set from JS to any value!
+    private final Object top_ = NOT_FOUND; // top can be set from JS to any value!
     private Crypto crypto_;
     private Scriptable performance_;
 

src/main/java/org/htmlunit/javascript/host/css/CSSStyleDeclaration.java

@@ -1957,8 +1957,6 @@ private void setStyleLengthAttribute(final String name, final Object value, fina
             return;
         }
 
-        final double doubleValue;
-        String unit = "px";
         if (value instanceof Number) {
             return;
         }
@@ -1985,7 +1983,8 @@ private void setStyleLengthAttribute(final String name, final Object value, fina
             return;
         }
 
-        if (percent && valueString.endsWith("%")) {
+        String unit = "px";
+                if (percent && valueString.endsWith("%")) {
             unit = valueString.substring(valueString.length() - 1);
             valueString = valueString.substring(0, valueString.length() - 1);
         }
@@ -2017,7 +2016,7 @@ else if (valueString.endsWith("rem")
             // we have a unit but surrounding blanks
             return;
         }
-        doubleValue = JavaScriptEngine.toNumber(valueString);
+        final double doubleValue = JavaScriptEngine.toNumber(valueString);
 
         try {
             if (Double.isNaN(doubleValue) || Double.isInfinite(doubleValue)) {

src/main/java/org/htmlunit/javascript/host/intl/DateTimeFormat.java

@@ -283,7 +283,7 @@ static final class DateTimeFormatHelper {
 
         private final DateTimeFormatter formatter_;
         private Chronology chronology_;
-        private String locale_;
+        private final String locale_;
 
         DateTimeFormatHelper(final String locale, final BrowserVersion browserVersion, final String pattern) {
             locale_ = locale;