자바키워드

1. abstract
2. class
3. interface
4. instanceof
5. main
6. null
7. package
8. private
9. public
10. protected
11. return
12. static
13. switch
14. for
15. while
16. if~else
17. this
18. super
19. try~catch
20. finally
21. throw
22. throws
23. void
24. main
25. implements
26. extends
27. float
28. double
29. byte
30. short
31. char
32. boolean
33. int
34. long
35. case
36. do
37. continue
38. break

자바개념

1. 상속 (inheritence)
2. 객체 (object)
3. 변수 (variable)
4. 상수 (literal)
5. 참조타입 (reference type)
6. 오버라이딩 (overriding)
7. 오버로딩 (overloading)
8. 다형성 (polymorphism)
9. 깊은복제 (deep clone)
10. 생성자 (constructor)
11. 캡슐화 (encapsulation)
12. 박싱/언방싱 (boxing/unboxing)
13. 쓰레기수집기 (Garbage Collector)
14. 게터/세터 (Getter/Setter)
15. 힙 (heap)
16. 스택 (stack)
17. 인스턴스 (instance)
18. 람다식 (Lambda Expressions)
19. 정규표현식 (Regular Expression)
20. 메소드 (method)
21. 매개변수 (parameter)
22. 멀티테스킹 (multi tasking)
23. 캐스팅 (casting)
24. 싱글톤 (singletone)
25. 예외처리 (exception)
26. 스태틱 (static)

알아야 할 클래스

1. Object
2. System
3. String
4. StringBuffer
5. StringBuilder
6. Math
7. Byte, Short
8. Boolean
9. Character
10. Integer, Long
11. Float, Double
12. Random
13. Calendar
14. Date
15. Arrays
16. StringTokenizer
17. Class
18. Pattern
19. DecimalFormat
20. SimpleDateFormat
21. MessageFormat
22. LocalDate
23. LocalTime
24. Period
25. Duration
26. Collections
27. List
28. Set
29. Map
30. Properties
31. Queue
32. Stream
33. File
34. Path
35. Iterator
36. Exception
37. Connection
38. Statement
39. ResultSet
40. Operator
41. Optional
42. Serializable
43. Scanner