167      */
 168     public StringBuilder append(StringBuffer sb) {
 169         super.append(sb);
 170         return this;
 171     }
 172 
 173     /**
 174      */
 175     public StringBuilder append(CharSequence s) {
 176         if (s == null)
 177             s = "null";
 178         if (s instanceof String)
 179             return this.append((String)s);
 180         if (s instanceof StringBuffer)
 181             return this.append((StringBuffer)s);
 182         if (s instanceof StringBuilder)
 183             return this.append((StringBuilder)s);
 184         return this.append(s, 0, s.length());
 185     }
 186 









 187     /**
 188      * @throws     IndexOutOfBoundsException {@inheritDoc}
 189      */
 190     public StringBuilder append(CharSequence s, int start, int end) {
 191         super.append(s, start, end);
 192         return this;
 193     }
 194 
 195     public StringBuilder append(char[] str) {
 196         super.append(str);
 197         return this;
 198     }
 199 
 200     /**
 201      * @throws IndexOutOfBoundsException {@inheritDoc}
 202      */
 203     public StringBuilder append(char[] str, int offset, int len) {
 204         super.append(str, offset, len);
 205         return this;
 206     }

 167      */
 168     public StringBuilder append(StringBuffer sb) {
 169         super.append(sb);
 170         return this;
 171     }
 172 
 173     /**
 174      */
 175     public StringBuilder append(CharSequence s) {
 176         if (s == null)
 177             s = "null";
 178         if (s instanceof String)
 179             return this.append((String)s);
 180         if (s instanceof StringBuffer)
 181             return this.append((StringBuffer)s);
 182         if (s instanceof StringBuilder)
 183             return this.append((StringBuilder)s);
 184         return this.append(s, 0, s.length());
 185     }
 186     
 187     /**
 188      * @throws IllegalArgumentException if n < 0  {@inheritDoc}
 189      * @since 1.8
 190      */
 191     public StringBuilder append(int n, CharSequence cs) {
 192         super.append(n, cs);
 193         return this;
 194     }   
 195     
 196     /**
 197      * @throws     IndexOutOfBoundsException {@inheritDoc}
 198      */
 199     public StringBuilder append(CharSequence s, int start, int end) {
 200         super.append(s, start, end);
 201         return this;
 202     }
 203 
 204     public StringBuilder append(char[] str) {
 205         super.append(str);
 206         return this;
 207     }
 208 
 209     /**
 210      * @throws IndexOutOfBoundsException {@inheritDoc}
 211      */
 212     public StringBuilder append(char[] str, int offset, int len) {
 213         super.append(str, offset, len);
 214         return this;
 215     }