Effective Java
• Creating and Destroying Objects创建和销毁对象
1. Consider static factory methods instead of constructors
考虑用静态工厂方法代替构造器
2. Consider a builder when faced with many constructor parameters
遇到多个构造器参数时要考虑用构建器
3. Enforce the singleton property with a private constructor or an enum type
用私有构造器或者枚举类型强化singleton属性
4. Enforce noninstantiability with a private constructor
通过私有构造器强化不可实例化的能力
5. Avoid creating unnecessary objects
避免创建不必要的对象
6. Eliminate obsolete object references
消除过期的对象引用
7. Avoid finalizers
避免使用终结函数
• Methods Common to All Objects对于所有对象都通用的方法
8. Obey the general contract when overriding equals
改写equals时请遵守通用约定
9. Always override hashCode when you override equals
改写equals时总要改写hashCode
10. Always override toString
始终要改写tostring
11. Override clone judiciously
谨慎地改写clone
12. Consider implementing Comparable
考虑实现Comparable接口
• Classes and Interfaces类和接口
13. Minimize the accessibility of classes and members
使类和成员的可访问性最小化
14. In public classes, use accessor methods, not public fields
在公有类中使用访问方法而非公有域
15. Minimize mutability
使非可变性最小化
16. Favor composition over inheritance
复合优先于继承
17. Design and document for inheritance or else prohibit it
要么为继承而设计，并提供文档说明，要么就禁止继承
18. Prefer interfaces to abstract classes
接口优于抽象类
19. Use interfaces only to define types
接口只用于定义类型
20. Prefer class hierarchies to tagged classes
类层次优于标签类
21. Use function objects to represent strategies
用函数对象表示策略
22. Favor static member classes over nonstatic
优先考虑静态成员类
• Generics泛型
23. Don’t use raw types in new code
请不要在新代码中使用原生态类型
24. Eliminate unchecked warnings
消除非受检警告
25. Prefer lists to arrays
列表优先于数组
26. Favor generic types
优先考虑泛型
27. Favor generic methods
优先考虑泛型方法
28. Use bounded wildcards to increase API flexibility
利用有限制通配符来提升API的灵活性
29. Consider typesafe heterogeneous containers
优先考虑类型安全的异构容器
• Enums and Annotations枚举和注解
30. Use enums instead of int constants
用enum代替int常量
31. Use instance fields instead of ordinals
用实例域代替序数
32. Use EnumSet instead of bit fields
用EnumSet代替位域
33. Use EnumMap instead of ordinal indexing
用EnumMap代替序数索引
34. Emulate extensible enums with interfaces
用接口模拟可伸缩的枚举
35. Prefer annotations to naming patterns
注解优先于命名模式
36. Consistently use the Override annotation
坚持使用override注解
37. Use marker interfaces to define types
用标记接口定义类型
• Methods方法
38. Check parameters for validity
检查参数的有效性
39. Make defensive copies when needed
必要时进行保护性拷贝
40. Design method signatures carefully
谨慎设计方法签名
41. Use overloading judiciously
慎用重载
42. Use varargs judiciously
慎用可变参数（varargs）
43. Return empty arrays or collections, not nulls
返回零长度的数组或者集合，而不是null
44. Write doc comments for all exposed API elements
为所有导出的API元素编写文档注释
• General Programming通用程序设计
45. Minimize the scope of local variables
将局部变量的作用域最小化
46. Prefer for-each loops to traditional for loops
for-each循环优先于传统的for循环
47. Know and use the libraries
了解和使用类库
48. Avoid float and double if exact answers are required
如果需要精确的答案，请避免使用float和double
49. Prefer primitive types to boxed primitives
原语类型优先于装箱的原语类型
50. Avoid strings where other types are more appropriate
如果其他类型更适合，则尽量避免使用字符串
51. Beware the performance of string concatenation
了解字符串连接的性能
52. Refer to objects by their interfaces
通过接口引用对象
53. Prefer interfaces to reflection
接口优先于反射机制
54. Use native methods judiciously
谨慎地使用本地方法
55. Optimize judiciously
谨慎地进行优化
56. Adhere to generally accepted naming conventions
遵守普遍接受的命名惯例
• Exceptions异常
57. Use exceptions only for exceptional conditions
只针对异常的条件才使用异常
58. Use checked exceptions for recoverable conditions and runtime exceptions for programming errors
对可恢复的条件使用受检异常，对编程错误使用运行时异常
59. Avoid unnecessary use of checked exceptions
避免不必要地使用受检的异常
60. Favor the use of standard exceptions
尽量使用标准的异常
61. Throw exceptions appropriate to the abstraction
抛出与抽象相对应的异常
62. Document all exceptions thrown by each method
每个方法抛出的所有异常都要有文档
63. Include failure-capture information in detail messages
在细节消息中包含失败－捕获信息
64. Strive for failure atomicity
努力使失败保持原子性
65. Don’t ignore exceptions
不要忽略异常
• Concurrency并发
66. Synchronize access to shared mutable data
同步访问共享的可变数据
67. Avoid excessive synchronization
避免过多同步
68. Prefer executors and tasks to threads
executor和task优先于线程
69. Prefer concurrency utilities to wait and notify
并发工具优先于wait和notify
70. Document thread safety
线程安全性的文档化
71. Use lazy initialization judiciously
慎用延迟初始化
72. Don’t depend on the thread scheduler
不要依赖于线程调度器
73. Avoid thread groups
避免使用线程组
• Serialization序列化
74. Implement Serializable judiciously
谨慎地实现serializable
75. Consider using a custom serialized form
考虑使用自定义的序列化形式
76. Write readObject methods defensively
保护性地编写readobject方法
77. For instance control, prefer enum types to readResolve
对于实例控制，枚举类型优先于readResolve
78. Consider serialization proxies instead of serialized instances
考虑用序列化代理代替序列化实例