--- old/src/share/classes/java/util/Formatter.java	Thu Dec 16 12:05:29 2010
+++ new/src/share/classes/java/util/Formatter.java	Thu Dec 16 12:05:28 2010
@@ -50,6 +50,8 @@
 import java.util.Locale;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.nio.charset.Charset;
+import java.nio.charset.IllegalCharsetNameException;
 
 import sun.misc.FpUtils;
 import sun.misc.DoubleConsts;
@@ -1838,11 +1840,11 @@
  */
 public final class Formatter implements Closeable, Flushable {
     private Appendable a;
-    private Locale l;
+    private final Locale l;
 
     private IOException lastException;
 
-    private char zero = '0';
+    private final char zero;
     private static double scaleUp;
 
     // 1 (sign) + 19 (max # sig digits) + 1 ('.') + 1 ('e') + 1 (sign)
@@ -1849,11 +1851,40 @@
     // + 3 (max # exp digits) + 4 (error) = 30
     private static final int MAX_FD_CHARS = 30;
 
-    // Initialize internal data.
-    private void init(Appendable a, Locale l) {
+    /**
+     * Verifies that the given charset is supported.
+     * @throws NullPointerException          is csn is null
+     * @throws UnsupportedEncodingException  if the charset is not supported
+     */
+    private static Void verifyCharsetName(String csn)
+            throws UnsupportedEncodingException {
+        Objects.nonNull(csn, "charsetName");
+        try {
+            if (Charset.isSupported(csn))
+                return null;
+        } catch (IllegalCharsetNameException unused) {
+            /* swallow this exception since UnsupportedEncodingException
+             * will be thrown */
+        }
+        throw new UnsupportedEncodingException(csn);
+    }
+
+    private static final Appendable nonNullAppendable(Appendable a) {
+        if (a == null)
+            return new StringBuilder();
+
+        return a;
+    }
+
+    // Private constructors
+    private Formatter(Void unused, Locale l, Appendable a) {
+        this(l, a);
+    }
+
+    private Formatter(Locale l, Appendable a) {
         this.a = a;
         this.l = l;
-        setZero();
+        this.zero = getZero(l);
     }
 
     /**
@@ -1867,7 +1898,7 @@
      * virtual machine.
      */
     public Formatter() {
-        init(new StringBuilder(), Locale.getDefault(Locale.Category.FORMAT));
+        this(Locale.getDefault(Locale.Category.FORMAT), new StringBuilder());
     }
 
     /**
@@ -1881,9 +1912,7 @@
      *         {@code null} then a {@link StringBuilder} will be created.
      */
     public Formatter(Appendable a) {
-        if (a == null)
-            a = new StringBuilder();
-        init(a, Locale.getDefault(Locale.Category.FORMAT));
+        this(Locale.getDefault(Locale.Category.FORMAT), nonNullAppendable(a));
     }
 
     /**
@@ -1900,7 +1929,7 @@
      *         is applied.
      */
     public Formatter(Locale l) {
-        init(new StringBuilder(), l);
+        this(l, new StringBuilder());
     }
 
     /**
@@ -1916,9 +1945,7 @@
      *         is applied.
      */
     public Formatter(Appendable a, Locale l) {
-        if (a == null)
-            a = new StringBuilder();
-        init(a, l);
+        this(l, nonNullAppendable(a));
     }
 
     /**
@@ -1949,8 +1976,8 @@
      *          creating the file
      */
     public Formatter(String fileName) throws FileNotFoundException {
-        init(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName))),
-             Locale.getDefault(Locale.Category.FORMAT));
+        this(Locale.getDefault(Locale.Category.FORMAT),
+             new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName))));
     }
 
     /**
@@ -2025,8 +2052,9 @@
     public Formatter(String fileName, String csn, Locale l)
         throws FileNotFoundException, UnsupportedEncodingException
     {
-        init(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName), csn)),
-             l);
+        this(verifyCharsetName(csn),
+             l,
+             new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName), csn)));
     }
 
     /**
@@ -2057,8 +2085,8 @@
      *          creating the file
      */
     public Formatter(File file) throws FileNotFoundException {
-        init(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file))),
-             Locale.getDefault(Locale.Category.FORMAT));
+        this(Locale.getDefault(Locale.Category.FORMAT),
+             new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file))));
     }
 
     /**
@@ -2133,8 +2161,9 @@
     public Formatter(File file, String csn, Locale l)
         throws FileNotFoundException, UnsupportedEncodingException
     {
-        init(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), csn)),
-             l);
+        this(verifyCharsetName(csn),
+             l,
+             new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), csn)));
     }
 
     /**
@@ -2151,9 +2180,8 @@
      *         The stream to use as the destination of this formatter.
      */
     public Formatter(PrintStream ps) {
-        if (ps == null)
-            throw new NullPointerException();
-        init((Appendable)ps, Locale.getDefault(Locale.Category.FORMAT));
+        this(Locale.getDefault(Locale.Category.FORMAT),
+             (Appendable)Objects.nonNull(ps));
     }
 
     /**
@@ -2171,8 +2199,8 @@
      *         The output will be buffered.
      */
     public Formatter(OutputStream os) {
-        init(new BufferedWriter(new OutputStreamWriter(os)),
-             Locale.getDefault(Locale.Category.FORMAT));
+        this(Locale.getDefault(Locale.Category.FORMAT),
+             new BufferedWriter(new OutputStreamWriter(os)));
     }
 
     /**
@@ -2222,13 +2250,15 @@
     public Formatter(OutputStream os, String csn, Locale l)
         throws UnsupportedEncodingException
     {
-        init(new BufferedWriter(new OutputStreamWriter(os, csn)), l);
+        this(l, new BufferedWriter(new OutputStreamWriter(os, csn)));
     }
 
-    private void setZero() {
+    private static final char getZero(Locale l) {
         if ((l != null) && !l.equals(Locale.US)) {
             DecimalFormatSymbols dfs = DecimalFormatSymbols.getInstance(l);
-            zero = dfs.getZeroDigit();
+            return dfs.getZeroDigit();
+        } else {
+            return '0';
         }
     }