13.
What is the purpose of the `FileWriter` class in Java?

15.
In Java, what is the primary purpose of the `DataInputStream` class?

16.
In Java, what does the `DataOutputStream` class do?

18.
What is the purpose of the `RandomAccessFile` class in Java?

19.
In Java, which class is used to read and write character streams?

20.
What is the primary purpose of the `File` class in Java?