IO is very important from Java interview point of view. You should have a good knowledge of old Java IO, NIO, and NIO2 along with some operating system and disk IO fundamentals. Here are some frequently asked questions form Java IO.

List questions:

1. In my Java program, I have three sockets? How many threads I will need to handle that?
2. How do you create ByteBuffer in Java?
3. How do you write and read from ByteBuffer in Java?
4. Is Java BIG endian or LITTLE endian?
5. What is the byte order of ByteBuffer?
6. The difference between direct buffer and non-direct buffer in Java?
7. What is the memory mapped buffer in Java?
8. What is TCP NO DELAY socket option?
9. What is the difference between TCP and UDP protocol?
10. The difference between ByteBuffer and StringBuffer in Java?
11. What is a stream and what are the types of Streams and classes of the Streams?
12. What is the difference between Reader/Writer and InputStream/Output Stream?
13. What is an I/O filter?

1. In my Java program, I have three sockets? How many threads I will need to handle that? ⤴

2. How do you create ByteBuffer in Java? ⤴

3. How do you write and read from ByteBuffer in Java? ⤴

4. Is Java BIG endian or LITTLE endian? ⤴

5. What is the byte order of ByteBuffer? ⤴

6. The difference between direct buffer and non-direct buffer in Java? ⤴

detail

1. What is the memory mapped buffer in Java? ⤴

detail

1. What is TCP NO DELAY socket option? ⤴

2. What is the difference between TCP and UDP protocol? ⤴

detail

1. The difference between ByteBuffer and StringBuffer in Java? ⤴

2. What is a stream and what are the types of Streams and classes of the Streams? ⤴

3. What is the difference between Reader/Writer and InputStream/Output Stream? ⤴

4. What is an I/O filter? ⤴