code: protected final String shaveOffNonJavaIdentifierStartChars( String str ) {
        String str2 = str;
        // shave off first char if not valid
        boolean ready = false;
        while( !ready ){
           if( !Character.isJavaIdentifierStart( str2.charAt( 0 ) ) ){
              str2 = str2.substring( 1 );
              if( str2.length() == 0 ){
                 throw new JSONException( "Can't convert '" + str + "' to a valid Java identifier" );
              }
           }else{
              ready = true;
           }
        }
        return str2;
     }
docs: Removes all non JavaIdentifier chars from the start of the string.
  
  @throws JSONException if the resulting string has zero length.