Pls help me to explain line 1, 4, 5, 6

Question

1. import java.io.*;
2. import java.util.Scanner;
3. public class Hello {
4. public static void main(String[ ] args) throws IOException {
5. InputStreamReader reader = new InputStreamReader(System.in);
6. BufferedReader input = new BufferedReader(reader);
7. System.out.print("Enter your name");
8. String name = input.readLine();
9. System.out.println ("Hello,"+ name + "!");
}
}

Answer 1

First line imports all the io(input output classes)
Line 4 is a main method..key for the program and it throws Input output exception if errors
Because io classes should be surround with try catch block or like this
Line 5 is a input class to get data from the user
Line 6 is a buffer reader reads the data from the input class