java lesson 01
https://www.youtube.com/watch?v=qhrCNVZYR1M
java lesson 02
https://www.youtube.com/watch?v=BPrVXcBK-QE
java lesson 03
https://www.youtube.com/watch?v=b4r1PDPogU0
java lesson 04
https://www.youtube.com/watch?v=8L5Jx19qK-I
java lesson 05
https://www.youtube.com/watch?v=BYjIIY9iZfQ
java lesson 06
https://www.youtube.com/watch?v=NSnkHYk8F1c