private static String next ( ) {
  while ( st == null || ! st . hasMoreElements ( ) ) {
    String s ;
    try {
      s = br . readLine ( ) ;
    }
    catch ( IOException e ) {
      return null ;
    }
    st = new StringTokenizer ( s ) ;
  }
  return st . nextToken ( ) ;
}

private static String next ( ) { while ( st == null || ! st . hasMoreElements ( ) ) { String s ; try { s = br . readLine ( ) ; } catch ( IOException e ) { return null ; } st = new StringTokenizer ( s ) ; } return st . nextToken ( ) ; }
(method_declaration (modifiers) type: (type_identifier) name: (identifier) parameters: (formal_parameters) body: (block (while_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (unary_expression operand: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier))) (try_statement body: (block (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))) (catch_clause (catch_formal_parameter (catch_type (type_identifier)) name: (identifier)) body: (block (return_statement (null_literal))))) (expression_statement (assignment_expression left: (identifier) right: (object_creation_expression type: (type_identifier) arguments: (argument_list (identifier))))))) (return_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))