diff --git a/jode/src/net/sf/jode/type/ReferenceType.java b/jode/src/net/sf/jode/type/ReferenceType.java
index d459a24..716a43f 100644
--- a/jode/src/net/sf/jode/type/ReferenceType.java
+++ b/jode/src/net/sf/jode/type/ReferenceType.java
@@ -26,7 +26,7 @@ import java.util.Vector;
 import java.util.Enumeration;
 
 /**
- * This is an abstrace super class of all reference types.  Reference
+ * This is an abstract super class of all reference types.  Reference
  * types are NullType, MultiClassType, and ClassType with its sub types
  * ClassInfoType, SystemClassType, and ArrayType. <p>
  *
diff --git a/jode/src/net/sf/jode/type/Type.java b/jode/src/net/sf/jode/type/Type.java
index a4c9dc4..7c6da75 100644
--- a/jode/src/net/sf/jode/type/Type.java
+++ b/jode/src/net/sf/jode/type/Type.java
@@ -175,6 +175,22 @@ public class Type {
 	tSystemClass("java.lang.Comparable", 
 		     null, EMPTY_IFACES, false, true);
 
+    /**
+     * This type represents the singleton set containing 
+     * <code>java.lang.Appendable</code>.
+     */
+    public static final SystemClassType tAppendable =
+	tSystemClass("java.lang.Appendable", 
+		     null, EMPTY_IFACES, false, true);
+
+    /**
+     * This type represents the singleton set containing 
+     * <code>java.lang.CharSequence</code>.
+     */
+    public static final SystemClassType tCharSequence =
+	tSystemClass("java.lang.CharSequence", 
+		     null, EMPTY_IFACES, false, true);
+
     /**
      * This type represents the singleton set containing 
      * <code>java.lang.String</code>.
@@ -182,7 +198,7 @@ public class Type {
     public static final SystemClassType tString =
 	tSystemClass("java.lang.String", 
 		     tObject, 
-		     new ClassType[] { tSerializable, tComparable },
+		     new ClassType[] { tSerializable, tComparable, tCharSequence },
 		     true, false);
     /**
      * This type represents the singleton set containing 
@@ -190,15 +206,15 @@ public class Type {
      */
     public static final SystemClassType tStringBuffer =
 	tSystemClass("java.lang.StringBuffer", 
-		     tObject, new ClassType[] { tSerializable },
+		     tObject, new ClassType[] { tSerializable, tAppendable, tCharSequence },
 		     true, false);
     /**
      * This type represents the singleton set containing 
-     * <code>java.lang.StringBuffer</code>.
+     * <code>java.lang.StringBuilder</code>.
      */
     public static final SystemClassType tStringBuilder =
 	tSystemClass("java.lang.StringBuilder", 
-		     tObject, new ClassType[] { tSerializable },
+		     tObject, new ClassType[] { tSerializable, tAppendable, tCharSequence },
 		     true, false);
     /**
      * This type represents the singleton set containing 
@@ -270,7 +286,7 @@ public class Type {
      * Generate the singleton set of the type represented by the given
      * class name.
      * @param clazzname the interned full qualified name of the class. 
-     * The packages mus be separated by `.'.
+     * The packages must be separated by `.'.
      * @return a singleton set containing the given type.
      */
     public static final SystemClassType tSystemClass