Remove unnecesary code

Following hints from IDE:
- remove ignored blank lines in javadoc
- remove unused variables
- inline variable
- simplify expressions that are always true

metafacture-biblio/src/main/java/org/metafacture/biblio/marc21/MarcXmlEncoder.java

@@ -49,9 +49,6 @@ public final class MarcXmlEncoder extends DefaultStreamPipe<ObjectReceiver<Strin
     public static final boolean OMIT_XML_DECLARATION = false;
     public static final boolean ENSURE_CORRECT_MARC21_XML = false;
 
-    private static final String ROOT_OPEN = "<marc:collection xmlns:marc=\"http://www.loc.gov/MARC21/slim\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:schemaLocation=\"http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd\">";
-    private static final String ROOT_CLOSE = "</marc:collection>";
-
     private enum Tag {
 
         collection(" xmlns%s=\"" + NAMESPACE + "\"%s"),
@@ -106,7 +103,6 @@ public String close(final Object[] args) {
     private static final int TAG_END = 3;
 
     private final Encoder encoder = new Encoder();
-    private final Marc21Decoder decoder = new Marc21Decoder();
     private final Marc21Encoder wrapper = new Marc21Encoder();
 
     private DefaultStreamPipe<ObjectReceiver<String>> pipe;
@@ -115,6 +111,7 @@ public String close(final Object[] args) {
      * Creates an instance of {@link MarcXmlEncoder}.
      */
     public MarcXmlEncoder() {
+        final Marc21Decoder decoder = new Marc21Decoder();
         decoder.setEmitLeaderAsWhole(true);
 
         wrapper
@@ -136,7 +133,6 @@ public void setEmitNamespace(final boolean emitNamespace) {
 
     /**
      * Sets the flag to decide whether to omit the XML declaration.
-     *
      * <strong>Default value: {@value #OMIT_XML_DECLARATION}</strong>
      *
      * @param currentOmitXmlDeclaration true if the XML declaration is omitted, otherwise
@@ -148,7 +144,6 @@ public void omitXmlDeclaration(final boolean currentOmitXmlDeclaration) {
 
     /**
      * Sets the XML version.
-     *
      * <strong>Default value: {@value #XML_VERSION}</strong>
      *
      * @param xmlVersion the XML version
@@ -159,7 +154,6 @@ public void setXmlVersion(final String xmlVersion) {
 
     /**
      * Sets the XML encoding.
-     *
      * <strong>Default value: {@value #XML_ENCODING}</strong>
      *
      * @param xmlEncoding the XML encoding
@@ -173,7 +167,6 @@ public void setXmlEncoding(final String xmlEncoding) {
      * If true, the input data is validated to ensure correct MARC21. Also the leader may be generated.
      * It acts as a wrapper: the input is piped to {@link org.metafacture.biblio.marc21.Marc21Encoder}, whose output is piped to {@link org.metafacture.biblio.marc21.Marc21Decoder}, whose output is piped to {@link org.metafacture.biblio.marc21.MarcXmlEncoder}.
      * This validation and treatment of the leader is more safe but comes with a performance impact.
-     *
      * <strong>Default value: {@value #ENSURE_CORRECT_MARC21_XML}</strong>
      *
      * @param ensureCorrectMarc21Xml if true the input data is validated to ensure correct MARC21. Also the leader may be generated.
@@ -184,7 +177,6 @@ public void setEnsureCorrectMarc21Xml(final boolean ensureCorrectMarc21Xml) {
 
     /**
      * Formats the resulting xml by indentation. Aka "pretty printing".
-     *
      * <strong>Default value: {@value #PRETTY_PRINTED}</strong>
      *
      * @param formatted true if formatting is activated, otherwise false
@@ -247,7 +239,7 @@ private static class Encoder extends DefaultStreamPipe<ObjectReceiver<String>> {
         private String currentEntity = "";
 
         private boolean emitNamespace = true;
-        private Object[] namespacePrefix = new Object[]{emitNamespace ? NAMESPACE_PREFIX : EMPTY};
+        private Object[] namespacePrefix = new Object[]{NAMESPACE_PREFIX};
 
         private int indentationLevel;
         private boolean formatted = PRETTY_PRINTED;
@@ -463,7 +455,6 @@ private void writeTagLeader(final Function<Object[], String> function) {
             writeRawLeader(function.apply(namespacePrefix));
         }
 
-
         private void prettyPrintIndentation() {
             if (formatted) {
                 final String prefix = String.join("", Collections.nCopies(indentationLevel, INDENT));