1. ~Java ~
@hakurai

3. stopRequested
Java HotSpot

4. while(!stopRequested){ if(!stopRequested){
i++; while(true){
} i++;
}
}

5. while(!stopRequested){ if(!stopRequested){
i++; while(true){
} i++;
}
}

8. Java
synchronized
volatile

9. synchronized
synchronized
synchronized

11. private final Object lock = new Object();
private List<String> list;
public void add(String text){
synchronized (lock){
listadd(text);
}
}

12. private final Object lock = new Object();
private List<String> list;
public void add(String text){
synchronized (lock){
listadd(text);
}
}

13. private final Object lock = new Object();
private List<String> list;
public void add(String text){
synchronized (lock){
listadd(text); lock
}
}

16. private final Object lock = new Object();
private List<String> list;
public String get(int index){
synchronized (lock){
return list.get(index);
}
}

17. private final Object lock = new Object();
private List<String> list;
public String get(int index){
synchronized (lock){
return list.get(index); list
}
}

18. private final Object lock = new Object();
private List<String> list;
public void add(String text){
synchronized (lock){
list.add(text);
}
}
public String get(int index){
return list.get(index);
}

19. private final Object lock = new Object();
private List<String> list;
public void add(String text){
synchronized (lock){
list.add(text);
list
}
}
IllegalArgumentException
public String get(int index){
return list.get(index);
}

20. private final Object lock = new Object();
private List<String> list;
public void add(String text){
synchronized (lock){
list.add(text);
list
}
}
IllegalArgumentException
public String get(int index){
return list.get(index);
}

21. // Java

22. 1
2
3
Java
null ( )

24. !
1 2 N

26. 1 2 N

27. T

28. (atomic)

29. from to

30. from to

35. 1

36. 1

37. 1

38. 2

39. 2

40. 2

41. 3

42. 3

43. 3

44. 4

45. 4

46. 4

47. 1

48. 2

49. 2

50. 2

51. 3
V T A
P
V T
B
Q

52. 3
P Q

53. 3
(1)P Q
P
(2)Q
(3)Q
(4)P

55. 1

56. 2
L T L
V T
V

57. private final Object lock = new Object();
private List<String> list;
private String get(int index){
synchronized (lock){
return list.get(index);
}
}

58. private final Object lock = new Object();
private List<String> list;
private String get(int index){
synchronized (lock){
return list.get(index); list
}
}

61. volatile
volatile

62. volatile 1
V T V
T
V T V
T

63. volatile 2
V T V
T
V T V
T

64. volatile
volatile

65. volatile 3
volatile (reordering)
private int num = 0;
private volatile boolean initialized;
public void run(){
num = 100;
initialized = true;
}

66. volatile 3
volatile (reordering)
private int num = 0;
private volatile boolean initialized;
public void run(){
num = 100; num
initialized = true;
}

67. volatile
Java

68. T

70. Java
Java
Effective Java