フリー問題

問題文

Which statement about the three standard streams of System is correct?

選択肢

1. All three are PrintStream instances, and the input one simply throws when a write is attempted on it.
2. The output one is buffered and flushed only when the program ends normally, so output produced before an uncaught exception is always lost.
3. All three are Reader and Writer instances, so characters are decoded and encoded without any additional wrapper being needed.
4. The input one is an InputStream while the output and error ones are PrintStream instances, so reading typically needs a wrapper that decodes characters.