Index: java/org/apache/catalina/connector/Request.java
===================================================================
--- java/org/apache/catalina/connector/Request.java	(revision 1137623)
+++ java/org/apache/catalina/connector/Request.java	(working copy)
@@ -1516,12 +1516,22 @@
 
         if (usingReader)
             return;
-        
-        // Ensure that the specified encoding is valid
-        byte buffer[] = new byte[1];
-        buffer[0] = (byte) 'a';
-        String dummy = new String(buffer, enc);
 
+        // Confirm that the encoding name is valid
+        try {
+            B2CConverter.getCharset(enc);
+        } catch (java.nio.charset.UnsupportedCharsetException e) {
+            UnsupportedEncodingException uee =
+                new UnsupportedEncodingException();
+            uee.initCause(e);
+            throw uee;
+        } catch (java.nio.charset.IllegalCharsetNameException e) {
+            UnsupportedEncodingException uee =
+                new UnsupportedEncodingException();
+            uee.initCause(e);
+            throw uee;
+        }
+
         // Save the validated encoding
         coyoteRequest.setCharacterEncoding(enc);
 
Index: java/org/apache/tomcat/util/buf/B2CConverter.java
===================================================================
--- java/org/apache/tomcat/util/buf/B2CConverter.java	(revision 1137623)
+++ java/org/apache/tomcat/util/buf/B2CConverter.java	(working copy)
@@ -21,7 +21,8 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
+import java.util.concurrent.ConcurrentHashMap;
 
 /** Efficient conversion of bytes  to character .
  *  
@@ -39,6 +40,9 @@
     
     private static org.apache.juli.logging.Log log=
         org.apache.juli.logging.LogFactory.getLog( B2CConverter.class );
+
+    private static final ConcurrentHashMap<String, Charset> encodingToCharsetCache =
+        new ConcurrentHashMap<String, Charset>();
     
     private IntermediateInputStream iis;
     private ReadConvertor conv;
@@ -114,7 +118,7 @@
     {
         // destroy the reader/iis
         iis=new IntermediateInputStream();
-        conv=new ReadConvertor( iis, encoding );
+        conv=new ReadConvertor( iis, getCharset(encoding) );
     }
 
     private final int debug=0;
@@ -123,6 +127,15 @@
             log.debug("B2CConverter: " + s );
     }
 
+    public static Charset getCharset(String enc) {
+        Charset charset = encodingToCharsetCache.get(enc);
+        if (charset == null) {
+            charset = Charset.forName(enc);
+            encodingToCharsetCache.put(enc, charset);
+        }
+        return charset;
+    }
+
     // -------------------- Not used - the speed improvemnt is quite small
 
     /*
@@ -192,10 +205,9 @@
     
     /** Create a converter.
      */
-    public ReadConvertor( IntermediateInputStream in, String enc )
-        throws UnsupportedEncodingException
+    public ReadConvertor( IntermediateInputStream in, Charset charset )
     {
-        super( in, enc );
+        super( in, charset );
     }
     
     /** Overriden - will do nothing but reset internal state.
@@ -224,6 +236,7 @@
         } catch(IOException ioe){
         }
     }
+
 }
 
 
Index: java/org/apache/tomcat/util/buf/ByteChunk.java
===================================================================
--- java/org/apache/tomcat/util/buf/ByteChunk.java	(revision 1137623)
+++ java/org/apache/tomcat/util/buf/ByteChunk.java	(working copy)
@@ -19,6 +19,8 @@
 
 import java.io.IOException;
 import java.io.Serializable;
+import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
 
 /*
  * In a server it is very important to be able to operate on
@@ -95,7 +97,12 @@
         8859_1, and this object is used mostly for servlets. 
     */
     public static final String DEFAULT_CHARACTER_ENCODING="ISO-8859-1";
-        
+
+    /** Default Charset to use for interpreting byte[] as as String
+    */
+    public static final Charset DEFAULT_CHARSET =
+        Charset.forName(DEFAULT_CHARACTER_ENCODING);
+    
     // byte[]
     private byte[] buff;
 
@@ -493,8 +500,14 @@
     public String toStringInternal() {
         String strValue=null;
         try {
-            if( enc==null ) enc=DEFAULT_CHARACTER_ENCODING;
-            strValue = new String( buff, start, end-start, enc );
+            Charset charset;
+            if (enc == null) {
+                charset = DEFAULT_CHARSET;
+            } else {
+                charset = B2CConverter.getCharset(enc);
+            }
+            strValue = charset.decode(
+                    ByteBuffer.wrap(buff, start, end-start)).toString();
             /*
              Does not improve the speed too much on most systems,
              it's safer to use the "clasical" new String().
@@ -507,7 +520,7 @@
              // Method is commented out, in:
               return B2CConverter.decodeString( enc );
               */
-        } catch (java.io.UnsupportedEncodingException e) {
+        } catch (java.nio.charset.UnsupportedCharsetException e) {
             // Use the platform encoding in that case; the usage of a bad
             // encoding will have been logged elsewhere already
             strValue = new String(buff, start, end-start);