first interview

computer network

1. Difference between TCP and UDP
2. Error code, such as 404, 502
3. The difference between get and post
4. How TCP establishes a connection
5. TCP window protocol

operating system

1. What kind of communication methods does Linus have?
2. Personal reasons, the interviewer did not ask

JAVA

1. Difference between interface and abstract class.
2. Methods and variables of interfaces and abstract classes.
3. The difference between modifiers, such as public, private.