static String duplicateVowels ( String str ) {
  int t = str . length ( ) ;
  String res = "" ;
  for ( int i = 0 ;
  i < t ;
  i ++ ) {
    if ( isVowel ( str . charAt ( i ) ) ) res += str . charAt ( i ) ;
    res += str . charAt ( i ) ;
  }
  return res ;
}

static String duplicateVowels ( String str ) { int t = str . length ( ) ; String res = " " ; for ( int i = 0 ; i < t ; i ++ ) { if ( isVowel ( str . charAt ( i ) ) ) res += str . charAt ( i ) ; res += str . charAt ( i ) ; } return res ; }
(method_declaration (modifiers) type: (type_identifier) 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)))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (string_literal))) (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 (if_statement condition: (parenthesized_expression (method_invocation name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))))) consequence: (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))))) (return_statement (identifier))))