static void convertOpposite ( StringBuffer str ) {
  int ln = str . length ( ) ;
  for ( int i = 0 ;
  i < ln ;
  i ++ ) {
    Character c = str . charAt ( i ) ;
    if ( Character . isLowerCase ( c ) ) str . replace ( i , i + 1 , Character . toUpperCase ( c ) + "" ) ;
    else str . replace ( i , i + 1 , Character . toLowerCase ( c ) + "" ) ;
  }
}

static void convertOpposite ( StringBuffer str ) { int ln = str . length ( ) ; for ( int i = 0 ; i < ln ; i ++ ) { Character c = str . charAt ( i ) ; if ( Character . isLowerCase ( c ) ) str . replace ( i , i + 1 , Character . toUpperCase ( c ) + " " ) ; else str . replace ( i , i + 1 , Character . toLowerCase ( c ) + " " ) ; } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier))) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) consequence: (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (identifier) right: (decimal_integer_literal)) (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (string_literal))))) alternative: (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (identifier) right: (decimal_integer_literal)) (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (string_literal))))))))))