private static int diff ( int num ) {
  return Math . abs ( FAVOURITE_NUMBER - num ) ;
}

private static int diff ( int num ) { return Math . abs ( FAVOURITE_NUMBER - num ) ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (return_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))))))