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Java 核心知识点

1. 目录

1. 目

录.............................................................................................................................

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JVM..........................................................................................................................

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线程 ...................................................................................................................................................... 20

内存区域 ..................................................................................................................................... 21

程序计数器线程私

有

虚拟机栈线程私

有

本地方法区线程私

有

堆（线程共享） 运行时数据区 



方法区永久代（线程共享）



运行时内存 ................................................................................................................................. 24

新生代



区....................................................................................................................................................24

...........................................................................................................................................24

..............................................................................................................................................24

的过程（复制清空互换） .......................................................................................24

： 、 复制到 ，年龄...................................................................................25

：清空 、 .............................................................................................................................25

： 和 互换................................................................................................................25

老年代



永久代

与元数据.................................................................................................................................25

垃圾回收与算法 .................................................................................................................................. 26

如何确定垃圾



引用计数法...............................................................................................................................................26

可达性分析...............................................................................................................................................26

标记清除算法（ !"）



复制算法（）



标记整理算法



分代收集算法



#新生代与复制算法 ..............................................................................................................................29

#老年代与标记复制算法 ......................................................................................................................29

#四中引用类型 ........................................................................................................................... 30

强引用



软引用

弱引用

虚引用

$分代收集算法 分区收集算法................................................................................................ 30

分代收集算法



$在新生代复制算法.............................................................................................................................30

$在老年代标记整理算法.....................................................................................................................30

分区收集算法



%垃圾收集器 ................................................................................................................................... 31

!"垃圾收集器（单线程、复制算法） 



#$%垃圾收集器（!"&多线程） 



#"""!'收集器（多线程复制算法、高效） 



!"(")收集器（单线程标记整理算法） 



#"""(")收集器（多线程标记整理算法） 



!收集器（多线程标记清除算法） 



%$初始标记..............................................................................................................................................33

&'&'()*

%$并发标记..............................................................................................................................................34

%$重新标记..............................................................................................................................................34

%$并发清除..............................................................................................................................................34

*收集

器

+,&-+,....................................................................................................................................... 34

阻塞 +(模型



非阻塞 +(模型



多路复用 +(模型



信号驱动 +(模型



异步 +(模型



,-.-+(

包

,-.-$+(



-+,的缓冲区 .....................................................................................................................................38

-+,的非阻塞 .....................................................................................................................................38

/"





012





!"



.类加载机制 ................................................................................................................................. 41

.加载 ..........................................................................................................................................................41

.验证 ..........................................................................................................................................................41

.准备 ..........................................................................................................................................................41

.解析 ..........................................................................................................................................................41

.#符号引用..............................................................................................................................................42

.$直接引用..............................................................................................................................................42

.%初始化 ......................................................................................................................................................42

.类构造器/01..............................................................................................................................42

类加载器



.启动类加载器2311"045.........................................................................................43

.扩展类加载器261045..........................................................................................43

.应用程序类加载器2""01045： ..........................................................................43

双亲委派



(!*+（动态模型系统）



.动态改变构造......................................................................................................................................44

.模块化编程与热插拔 ..........................................................................................................................44

3. JAVA 集

合.............................................................................................................................

...............45

接口继承关系和实现 .......................................................................................................................... 45

4+....................................................................................................................................................... 47

-34（数组）



.（数组实现、线程同步） 



334（链表）



....................................................................................................................................................... 48

781（78表） .............................................................................................................................48

1（二叉树） ................................................................................................................................49

4 781（7814 78"） ...................................................................................49

(....................................................................................................................................................... 50

4/（数组&链表&红黑树）



%实现 .............................................................................................................................................50

实现 .............................................................................................................................................51



14/

)1段..............................................................................................................................................51

线程安全（)1继承 9114 加锁） ..............................................................................51

并行度（默认 $） .................................................................................................................................52

实现（引入了红黑树） ..............................................................................................................52

&'&'()*

4/56"（线程安全）



5（可排序）



34/（记录插入顺序） 



4. JAVA 多线程并

发.............................................................................................................................

....54

,-.-并发知识库



,-.-线程实现创建方式 



继承 8类........................................................................................................................................54

实现 9:;0接口。 ............................................................................................................................54

6:1、 00;0/0、 :1:有返回值线程.............................................................55

基于线程池的方式...................................................................................................................................56

种线程池



!88(0.........................................................................................................................57

!68(0.............................................................................................................................57

!8:08(0....................................................................................................................58

!)086:1.................................................................................................................58

线程生命周期状

态

新建状态（ -<） .................................................................................................................................58

就绪状态（ 9=--34）： .................................................................................................................59

运行状态（ 9=--+-）： ....................................................................................................................59

阻塞状态（ 34,>?）： ....................................................................................................................59

等待阻塞（ !1等待对列）： ......................................................................................................................59

同步阻塞20 锁池5..........................................................................................................................................59

其他阻塞20"&@5............................................................................................................................................59

#线程死亡（ ??） ................................................................................................................................59

正常结束................................................................................................................................................................59

异常结束................................................................................................................................................................59

调用 1"...............................................................................................................................................................59

终止线程 种方式



#正常运行结束...........................................................................................................................................60

#使用退出标志退出线程...........................................................................................................................60

#+1:"1方法结束线程...........................................................................................................................60

#1"方法终止线程（线程不安全） .......................................................................................................61

4"与 %区

别

4与 1区别



,-.-后台线程



,-.-锁



.乐观锁 ......................................................................................................................................................63

.悲观锁 ......................................................................................................................................................63

.自旋锁 ......................................................................................................................................................63

自旋锁的优缺点....................................................................................................................................................63

自旋锁时间阈值（ $引入了适应性自旋锁） ..................................................................................................63

自旋锁的开启........................................................................................................................................................64

.A8B同步锁..............................................................................................................................64

A8B作用范围.......................................................................................................................................64

A8B核心组件.......................................................................................................................................64

A8B实现...............................................................................................................................................64

剩余63页未读，继续阅读

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