diff --git a/codec/src/main/java/io/netty/handler/codec/DefaultTextHeaders.java b/codec/src/main/java/io/netty/handler/codec/DefaultTextHeaders.java
index 64fa6010bc..450fac31e3 100644
--- a/codec/src/main/java/io/netty/handler/codec/DefaultTextHeaders.java
+++ b/codec/src/main/java/io/netty/handler/codec/DefaultTextHeaders.java
@@ -377,16 +377,20 @@ public class DefaultTextHeaders implements TextHeaders {
     }
 
     @Override
-    public int getInt(CharSequence name) {
+    public Integer getInt(CharSequence name) {
         CharSequence v = getUnconverted(name);
         if (v == null) {
-            throw new NoSuchElementException(String.valueOf(name));
+            return null;
         }
 
-        if (v instanceof AsciiString) {
-            return ((AsciiString) v).parseInt();
-        } else {
-            return Integer.parseInt(v.toString());
+        try {
+            if (v instanceof AsciiString) {
+                return ((AsciiString) v).parseInt();
+            } else {
+                return Integer.parseInt(v.toString());
+            }
+        } catch (NumberFormatException ignored) {
+            return null;
         }
     }
 
@@ -409,16 +413,20 @@ public class DefaultTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getLong(CharSequence name) {
+    public Long getLong(CharSequence name) {
         CharSequence v = getUnconverted(name);
         if (v == null) {
-            throw new NoSuchElementException(String.valueOf(name));
+            return null;
         }
 
-        if (v instanceof AsciiString) {
-            return ((AsciiString) v).parseLong();
-        } else {
-            return Long.parseLong(v.toString());
+        try {
+            if (v instanceof AsciiString) {
+                return ((AsciiString) v).parseLong();
+            } else {
+                return Long.parseLong(v.toString());
+            }
+        } catch (NumberFormatException ignored) {
+            return null;
         }
     }
 
@@ -441,13 +449,17 @@ public class DefaultTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getTimeMillis(CharSequence name) {
+    public Long getTimeMillis(CharSequence name) {
         CharSequence v = getUnconverted(name);
         if (v == null) {
-            throw new NoSuchElementException(String.valueOf(name));
+            return null;
         }
 
-        return HttpHeaderDateFormat.get().parse(v.toString());
+        try {
+            return HttpHeaderDateFormat.get().parse(v.toString());
+        } catch (ParseException ignored) {
+            return null;
+        }
     }
 
     @Override
@@ -529,16 +541,20 @@ public class DefaultTextHeaders implements TextHeaders {
     }
 
     @Override
-    public int getIntAndRemove(CharSequence name) {
+    public Integer getIntAndRemove(CharSequence name) {
         CharSequence v = getUnconvertedAndRemove(name);
         if (v == null) {
-            throw new NoSuchElementException(String.valueOf(name));
+            return null;
         }
 
-        if (v instanceof AsciiString) {
-            return ((AsciiString) v).parseInt();
-        } else {
-            return Integer.parseInt(v.toString());
+        try {
+            if (v instanceof AsciiString) {
+                return ((AsciiString) v).parseInt();
+            } else {
+                return Integer.parseInt(v.toString());
+            }
+        } catch (NumberFormatException ignored) {
+            return null;
         }
     }
 
@@ -561,16 +577,20 @@ public class DefaultTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getLongAndRemove(CharSequence name) {
+    public Long getLongAndRemove(CharSequence name) {
         CharSequence v = getUnconvertedAndRemove(name);
         if (v == null) {
-            throw new NoSuchElementException(String.valueOf(name));
+            return null;
         }
 
-        if (v instanceof AsciiString) {
-            return ((AsciiString) v).parseLong();
-        } else {
-            return Long.parseLong(v.toString());
+        try {
+            if (v instanceof AsciiString) {
+                return ((AsciiString) v).parseLong();
+            } else {
+                return Long.parseLong(v.toString());
+            }
+        } catch (NumberFormatException ignored) {
+            return null;
         }
     }
 
@@ -593,13 +613,17 @@ public class DefaultTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getTimeMillisAndRemove(CharSequence name) {
+    public Long getTimeMillisAndRemove(CharSequence name) {
         CharSequence v = getUnconvertedAndRemove(name);
         if (v == null) {
-            throw new NoSuchElementException(String.valueOf(name));
+            return null;
         }
 
-        return HttpHeaderDateFormat.get().parse(v.toString());
+        try {
+            return HttpHeaderDateFormat.get().parse(v.toString());
+        } catch (ParseException ignored) {
+            return null;
+        }
     }
 
     @Override
@@ -1074,7 +1098,7 @@ public class DefaultTextHeaders implements TextHeaders {
             dateFormat3.setTimeZone(tz);
         }
 
-        long parse(String text) {
+        long parse(String text) throws ParseException {
             Date date = dateFormat1.parse(text, parsePos);
             if (date == null) {
                 date = dateFormat2.parse(text, parsePos);
@@ -1083,7 +1107,7 @@ public class DefaultTextHeaders implements TextHeaders {
                 date = dateFormat3.parse(text, parsePos);
             }
             if (date == null) {
-                PlatformDependent.throwException(new ParseException(text, 0));
+                throw new ParseException(text, 0);
             }
             return date.getTime();
         }
diff --git a/codec/src/main/java/io/netty/handler/codec/EmptyTextHeaders.java b/codec/src/main/java/io/netty/handler/codec/EmptyTextHeaders.java
index b0249083d0..307f85415c 100644
--- a/codec/src/main/java/io/netty/handler/codec/EmptyTextHeaders.java
+++ b/codec/src/main/java/io/netty/handler/codec/EmptyTextHeaders.java
@@ -20,7 +20,6 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map.Entry;
-import java.util.NoSuchElementException;
 import java.util.Set;
 
 public class EmptyTextHeaders implements TextHeaders {
@@ -38,8 +37,8 @@ public class EmptyTextHeaders implements TextHeaders {
     }
 
     @Override
-    public int getInt(CharSequence name) {
-        throw new NoSuchElementException(String.valueOf(name));
+    public Integer getInt(CharSequence name) {
+        return null;
     }
 
     @Override
@@ -48,8 +47,8 @@ public class EmptyTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getLong(CharSequence name) {
-        throw new NoSuchElementException(String.valueOf(name));
+    public Long getLong(CharSequence name) {
+        return null;
     }
 
     @Override
@@ -58,8 +57,8 @@ public class EmptyTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getTimeMillis(CharSequence name) {
-        throw new NoSuchElementException(String.valueOf(name));
+    public Long getTimeMillis(CharSequence name) {
+        return null;
     }
 
     @Override
@@ -78,8 +77,8 @@ public class EmptyTextHeaders implements TextHeaders {
     }
 
     @Override
-    public int getIntAndRemove(CharSequence name) {
-        throw new NoSuchElementException(String.valueOf(name));
+    public Integer getIntAndRemove(CharSequence name) {
+        return null;
     }
 
     @Override
@@ -88,8 +87,8 @@ public class EmptyTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getLongAndRemove(CharSequence name) {
-        throw new NoSuchElementException(String.valueOf(name));
+    public Long getLongAndRemove(CharSequence name) {
+        return null;
     }
 
     @Override
@@ -98,8 +97,8 @@ public class EmptyTextHeaders implements TextHeaders {
     }
 
     @Override
-    public long getTimeMillisAndRemove(CharSequence name) {
-        throw new NoSuchElementException(String.valueOf(name));
+    public Long getTimeMillisAndRemove(CharSequence name) {
+        return null;
     }
 
     @Override
diff --git a/codec/src/main/java/io/netty/handler/codec/TextHeaders.java b/codec/src/main/java/io/netty/handler/codec/TextHeaders.java
index 97d9740f5e..06d9f3d212 100644
--- a/codec/src/main/java/io/netty/handler/codec/TextHeaders.java
+++ b/codec/src/main/java/io/netty/handler/codec/TextHeaders.java
@@ -35,104 +35,165 @@ public interface TextHeaders extends Iterable<Map.Entry<String, String>> {
      * Returns the value of a header with the specified name.  If there are
      * more than one values for the specified name, the first value is returned.
      *
-     * @param name The name of the header to search
-     * @return The first header value or {@code null} if there is no such header
+     * @param name the name of the header to search
+     * @return the first header value if the header is found.
+     *         {@code null} if there's no such header.
      */
     String get(CharSequence name);
 
+    /**
+     * Returns the value of a header with the specified name.  If there are
+     * more than one values for the specified name, the first value is returned.
+     *
+     * @param name the name of the header to search
+     * @param defaultValue the default value
+     * @return the first header value if the header is found.
+     *         {@code defaultValue} if there's no such header.
+     */
     String get(CharSequence name, String defaultValue);
-    int getInt(CharSequence name);
-    int getInt(CharSequence name, int defaultValue);
-    long getLong(CharSequence name);
-    long getLong(CharSequence name, long defaultValue);
-    long getTimeMillis(CharSequence name);
-    long getTimeMillis(CharSequence name, long defaultValue);
 
     /**
-     * Returns and Removes the value of a header with the specified name.  If there are
+     * Returns the integer value of a header with the specified name.  If there are
+     * more than one values for the specified name, the first value is returned.
+     *
+     * @param name the name of the header to search
+     * @return the first header value if the header is found and its value is an integer.
+     *         {@code null} if there's no such header or its value is not an integer.
+     */
+    Integer getInt(CharSequence name);
+
+    /**
+     * Returns the integer value of a header with the specified name.  If there are
+     * more than one values for the specified name, the first value is returned.
+     *
+     * @param name the name of the header to search
+     * @param defaultValue the default value
+     * @return the first header value if the header is found and its value is an integer.
+     *         {@code defaultValue} if there's no such header or its value is not an integer.
+     */
+    int getInt(CharSequence name, int defaultValue);
+
+    /**
+     * Returns the long integer value of a header with the specified name.  If there are
+     * more than one values for the specified name, the first value is returned.
+     *
+     * @param name the name of the header to search
+     * @return the first header value if the header is found and its value is a long integer.
+     *         {@code null} if there's no such header or its value is not a long integer.
+     */
+    Long getLong(CharSequence name);
+
+    /**
+     * Returns the long integer value of a header with the specified name.  If there are
+     * more than one values for the specified name, the first value is returned.
+     *
+     * @param name the name of the header to search
+     * @param defaultValue the default value
+     * @return the first header value if the header is found and its value is a long integer.
+     *         {@code defaultValue} if there's no such header or its value is not a long integer.
+     */
+    long getLong(CharSequence name, long defaultValue);
+
+    /**
+     * Returns the date value of a header with the specified name as milliseconds.  If there are
      * more than one values for the specified name, the first value is returned.
      *
      * @param name The name of the header to search
-     * @return The first header value or {@code null} if there is no such header
+     * @return the first header value in milliseconds if the header is found and its value is a date.
+     *         {@code null} if there's no such header or its value is not a date.
+     */
+    Long getTimeMillis(CharSequence name);
+
+    /**
+     * Returns the date value of a header with the specified name as milliseconds.  If there are
+     * more than one values for the specified name, the first value is returned.
+     *
+     * @param name The name of the header to search
+     * @param defaultValue default value
+     * @return the first header value in milliseconds if the header is found and its value is a date.
+     *         {@code defaultValue} if there's no such header or its value is not a date.
+     */
+    long getTimeMillis(CharSequence name, long defaultValue);
+
+    /**
+     * Returns and removes the value of a header with the specified name.  If there are
+     * more than one values for the specified name, the first value is returned.
+     *
+     * @param name the name of the header to search
+     * @return the first header value or {@code null} if there is no such header
      */
     String getAndRemove(CharSequence name);
 
     /**
-     * Returns and Removes the value of a header with the specified name.  If there are
+     * Returns and removes the value of a header with the specified name.  If there are
      * more than one values for the specified name, the first value is returned.
      *
-     * @param name The name of the header to search
-     * @param defaultValue default value
-     * @return The first header value or {@code defaultValue} if there is no such header
+     * @param name the name of the header to search
+     * @param defaultValue the default value
+     * @return the first header value or {@code defaultValue} if there is no such header
      */
     String getAndRemove(CharSequence name, String defaultValue);
 
     /**
-     * Returns and Removes the integer value of a header with the specified name.  If there are
+     * Returns and removes the integer value of a header with the specified name.  If there are
      * more than one values for the specified name, the first value is returned.
      *
-     * @param name The name of the header to search
-     * @return The first header value
-     * @throws java.util.NoSuchElementException
-     *         if no such header
-     * @throws NumberFormatException
-     *         if the value of header is not number
+     * @param name the name of the header to search
+     * @return the first header value if the header is found and its value is an integer.
+     *         {@code null} if there's no such header or its value is not an integer.
      */
-    int getIntAndRemove(CharSequence name);
+    Integer getIntAndRemove(CharSequence name);
 
     /**
-     * Returns and Removes the integer value of a header with the specified name.  If there are more than one values for
+     * Returns and removes the integer value of a header with the specified name.  If there are more than one values for
      * the specified name, the first value is returned.
      *
-     * @param name The name of the header to search
-     * @param defaultValue default value
-     * @return The first header value or {@code defaultValue} if there is no such header or the value of header is not
-     * number
+     * @param name the name of the header to search
+     * @param defaultValue the default value
+     * @return the first header value if the header is found and its value is an integer.
+     *         {@code defaultValue} if there is no such header or its value of header is not an integer.
      */
     int getIntAndRemove(CharSequence name, int defaultValue);
 
     /**
-     * Returns and Removes the long value of a header with the specified name.  If there are
+     * Returns and removes the long value of a header with the specified name.  If there are
      * more than one values for the specified name, the first value is returned.
      *
-     * @param name The name of the header to search
-     * @return The first header value
-     * @throws java.util.NoSuchElementException
-     *         if no such header
-     * @throws NumberFormatException
-     *         if the value of header is not number
+     * @param name the name of the header to search
+     * @return the first header value if the header is found and its value is an integer.
+     *         {@code null} if there's no such header or its value is not an integer.
      */
-    long getLongAndRemove(CharSequence name);
+    Long getLongAndRemove(CharSequence name);
 
     /**
-     * Returns and Removes the long value of a header with the specified name.  If there are more than one values for
+     * Returns and removes the long value of a header with the specified name.  If there are more than one values for
      * the specified name, the first value is returned.
      *
-     * @param name The name of the header to search
-     * @param defaultValue default value
-     * @return The first header value or {@code defaultValue} if there is no such header or the value of header is not
-     * number
+     * @param name the name of the header to search
+     * @param defaultValue the default value
+     * @return the first header value if the header is found and its value is an integer.
+     *         {@code defaultValue} if there's no such header or its value is not an integer.
      */
     long getLongAndRemove(CharSequence name, long defaultValue);
 
     /**
-     * Returns and Removes the millisecond value of a header with the specified name.  If there are
+     * Returns and removes the date value of a header with the specified name as milliseconds.  If there are
      * more than one values for the specified name, the first value is returned.
      *
      * @param name The name of the header to search
-     * @return The first header value
-     * @throws java.util.NoSuchElementException
-     *         if no such header
+     * @return the first header value in milliseconds if the header is found and its value is a date.
+     *         {@code null} if there's no such header or its value is not a date.
      */
-    long getTimeMillisAndRemove(CharSequence name);
+    Long getTimeMillisAndRemove(CharSequence name);
 
     /**
-     * Returns and Removes the millisecond value of a header with the specified name.  If there are more than one values
-     * for the specified name, the first value is returned.
+     * Returns and removes the date value of a header with the specified name as milliseconds.  If there are
+     * more than one values for the specified name, the first value is returned.
      *
      * @param name The name of the header to search
      * @param defaultValue default value
-     * @return The first header value or {@code defaultValue} if there is no such header
+     * @return the first header value in milliseconds if the header is found and its value is a date.
+     *         {@code defaultValue} if there's no such header or its value is not a date.
      */
     long getTimeMillisAndRemove(CharSequence name, long defaultValue);
 
@@ -201,17 +262,20 @@ public interface TextHeaders extends Iterable<Map.Entry<String, String>> {
     List<Entry<CharSequence, CharSequence>> unconvertedEntries();
 
     /**
-     * Checks to see if there is a header with the specified name
+     * Returns {@code true} if and only if this collection contains the header with the specified name.
      *
      * @param name The name of the header to search for
-     * @return True if at least one header is found
+     * @return {@code true} if at least one header is found
      */
     boolean contains(CharSequence name);
 
+    /**
+     * Returns the number of header entries in this collection.
+     */
     int size();
 
     /**
-     * Checks if no header exists.
+     * Returns {@code true} if and only if this collection contains no header entries.
      */
     boolean isEmpty();
 
@@ -237,8 +301,8 @@ public interface TextHeaders extends Iterable<Map.Entry<String, String>> {
      * of {@link java.util.Date} and {@link java.util.Calendar}, which are formatted to the date
      * format defined in <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3.1">RFC2616</a>.
      *
-     * @param name The name of the header being added
-     * @param value The value of the header being added
+     * @param name the name of the header being added
+     * @param value the value of the header being added
      *
      * @return {@code this}
      */
@@ -257,12 +321,29 @@ public interface TextHeaders extends Iterable<Map.Entry<String, String>> {
      * }
      * </pre>
      *
-     * @param name The name of the headepublic abstract rs being set
-     * @param values The values of the headers being set
+     * @param name the name of the headepublic abstract rs being set
+     * @param values the values of the headers being set
      * @return {@code this}
      */
     TextHeaders add(CharSequence name, Iterable<?> values);
 
+    /**
+     * Adds a new header with the specified name and values.
+     *
+     * This getMethod can be represented approximately as the following code:
+     * <pre>
+     * for (Object v: values) {
+     *     if (v == null) {
+     *         break;
+     *     }
+     *     headers.add(name, v);
+     * }
+     * </pre>
+     *
+     * @param name the name of the headepublic abstract rs being set
+     * @param values the values of the headers being set
+     * @return {@code this}
+     */
     TextHeaders add(CharSequence name, Object... values);
 
     /**
@@ -302,12 +383,31 @@ public interface TextHeaders extends Iterable<Map.Entry<String, String>> {
      * }
      * </pre>
      *
-     * @param name The name of the headers being set
-     * @param values The values of the headers being set
+     * @param name the name of the headers being set
+     * @param values the values of the headers being set
      * @return {@code this}
      */
     TextHeaders set(CharSequence name, Iterable<?> values);
 
+    /**
+     * Sets a header with the specified name and values.
+     *
+     * If there is an existing header with the same name, it is removed.
+     * This getMethod can be represented approximately as the following code:
+     * <pre>
+     * headers.remove(name);
+     * for (Object v: values) {
+     *     if (v == null) {
+     *         break;
+     *     }
+     *     headers.add(name, v);
+     * }
+     * </pre>
+     *
+     * @param name the name of the headers being set
+     * @param values the values of the headers being set
+     * @return {@code this}
+     */
     TextHeaders set(CharSequence name, Object... values);
 
     /**
@@ -335,12 +435,19 @@ public interface TextHeaders extends Iterable<Map.Entry<String, String>> {
     /**
      * Returns {@code true} if a header with the name and value exists.
      *
-     * @param name              the headername
-     * @param value             the value
+     * @param name              the header name
+     * @param value             the header value
      * @return {@code true} if it contains it {@code false} otherwise
      */
     boolean contains(CharSequence name, Object value);
 
+    /**
+     * Returns {@code true} if a header with the name and value exists.
+     *
+     * @param name              the header name
+     * @param value             the header value
+     * @return {@code true} if it contains it {@code false} otherwise
+     */
     boolean contains(CharSequence name, Object value, boolean ignoreCase);
 
     @Override