code: public boolean isInEncoding(char high, char low) {
          if (m_encoding == null) {
              m_encoding = new EncodingImpl();
              
              // One could put alternate logic in here to
              // instantiate another object that implements the
              // InEncoding interface. For example if the JRE is 1.4 or up
              // we could have an object that uses JRE 1.4 methods
          }
          return m_encoding.isInEncoding(high, low); 
      }
docs: This is not a public API. It returns true if the
  character formed by the high/low pair is in the encoding.
  @param high a char that the a high char of a high/low surrogate pair.
  @param low a char that is the low char of a high/low surrogate pair.
  <p>
  This method is not a public API.
  @xsl.usage internal