Use StringBuilder instead of StringBuffer.

Use final.

Author: garydgregory

src/main/java/org/apache/commons/io/IOCase.java

@@ -66,7 +66,7 @@ public enum IOCase {
 
     /**
      * Tests for cases sensitivity in a null-safe manner.
-     * 
+     *
      * @param caseSensitivity an IOCase.
      * @return true if the input is non-null and {@link #isCaseSensitive()}.
      * @since 2.10.0

src/main/java/org/apache/commons/io/filefilter/RegexFileFilter.java

@@ -96,7 +96,7 @@ private static int toFlags(final IOCase caseSensitivity) {
 
     /** The regular expression pattern that will be used to match file names. */
     private final Pattern pattern;
-    
+
     /** How convert a path to a string. */
     private final Function<Path, String> pathToString;
 

src/main/java/org/apache/commons/io/input/XmlStreamReader.java

@@ -214,7 +214,7 @@ private static String getXmlProlog(final InputStream inputStream, final String g
                 inputStream.reset();
                 final BufferedReader bReader = new BufferedReader(new StringReader(
                         xmlProlog.substring(0, firstGT + 1)));
-                final StringBuffer prolog = new StringBuffer();
+                final StringBuilder prolog = new StringBuilder();
                 String line;
                 while ((line = bReader.readLine()) != null) {
                     prolog.append(line);

src/test/java/org/apache/commons/io/input/compatibility/XmlStreamReader.java

@@ -689,7 +689,7 @@ private static String getXmlProlog(final BufferedInputStream is, final String gu
                 is.reset();
                 final BufferedReader bReader = new BufferedReader(new StringReader(
                         xmlProlog.substring(0, firstGT + 1)));
-                final StringBuffer prolog = new StringBuffer();
+                final StringBuilder prolog = new StringBuilder();
                 String line;
                 while ((line = bReader.readLine()) != null) {
                     prolog.append(line);