0. This is Java - List

This-is-Java

1. settings, concept, remark
2. data type basic
   
3. operator
4. condition statement
5. data type advance, memory area, operator for reference variable, NullPointException, String type, Array Type
6. Object, Class, field, constructor, method, this, static, final, package, access modifier, getter/setter, annotation
7. inheritance, polymorphism, Abstract Class
8. Interface, polymorphism
9. Nested Class/Interface, Anonymous Object
10. Exception
11. java docs, Object(s), System, Class, String, regex, Arrays, Wrapper, Math, Random, Date, Calendar, Format, java.time package
12. Thread
13. Generic
14. Lambda, Target, Functional Interface, Class member, local variable, API interface, method reference
15. Collections - List, Set, Map, search, LIFO/FIFO
16. Stream, parallel processing
17. JavaFX
18. I/O, file, network
19. NIO, buffer, file channel, blocking