Here is how to get user input to java program using BufferedReader implementation and descripion as a comment

BufferedReader.java

package SLCoder;

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Buffer {

	public static void main(String[] args)throws Exception {
		
		//System.in get default input device - keyboard
		//InputStreamReader create characters from collecting bytes
		//then BufferedReader collect characters and make text line
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		
		System.out.print("Enter your name here: ");
		//readLine() is the method in BufferedReader class and it will create String text
		// and here string add to the name variable
		//reader is our object
		String name = reader.readLine();
		
		System.out.print("How old are you? ");
		
		//I converted the input into integer because BufferedReader only get input as
		//String. So if we want another data types we have to conver into that we want type
		//Integer.parseInt() is a wrapper class for int
		int age = Integer.parseInt(reader.readLine());
		
		//here I check user input age is greater than the 18 then I will print the message
		if(age > 18){
			System.out.println(name + " You are adult person");
		}else{
			System.out.println("You are a little boy!");
		}
		
		//Using BufferedStream you can get any type of input and do manipulation
		//If you want to get another data type like double
		
		System.out.println("Enter your salary: ");
		// like that you can use any data type
		//but keep remember you have to change it to your variable type
		//because of readLine() only take String
		double salary = Double.parseDouble(reader.readLine());
		System.out.println(salary);
	}

}