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@ -16,7 +16,7 @@
* [访问权限](#访问权限) * [访问权限](#访问权限)
* [抽象类与接口](#抽象类与接口) * [抽象类与接口](#抽象类与接口)
* [super](#super) * [super](#super)
* [覆盖与重载](#覆盖与重载) * [重写与重载](#重写与重载)
* [五、Object 通用方法](#五object-通用方法) * [五、Object 通用方法](#五object-通用方法)
* [概览](#概览) * [概览](#概览)
* [equals()](#equals) * [equals()](#equals)
@ -494,7 +494,8 @@ System.out.println(InterfaceExample.x);
在很多情况下，接口优先于抽象类，因为接口没有抽象类严格的类层次结构要求，可以灵活地为一个类添加行为。并且从 Java 8 开始，接口也可以有默认的方法实现，使得修改接口的成本也变的很低。 在很多情况下，接口优先于抽象类，因为接口没有抽象类严格的类层次结构要求，可以灵活地为一个类添加行为。并且从 Java 8 开始，接口也可以有默认的方法实现，使得修改接口的成本也变的很低。
> [深入理解 abstract class 和 interface](https://www.ibm.com/developerworks/cn/java/l-javainterface-abstract/) </br> [When to Use Abstract Class and Interface](https://dzone.com/articles/when-to-use-abstract-class-and-intreface) - [深入理解 abstract class 和 interface](https://www.ibm.com/developerworks/cn/java/l-javainterface-abstract/)
- [When to Use Abstract Class and Interface](https://dzone.com/articles/when-to-use-abstract-class-and-intreface)
## super ## super
@ -544,11 +545,11 @@ SuperExample.func()
SuperExtendExample.func() SuperExtendExample.func()
``` ```
> [Using the Keyword super](https://docs.oracle.com/javase/tutorial/java/IandI/super.html) [Using the Keyword super](https://docs.oracle.com/javase/tutorial/java/IandI/super.html)
## 覆盖与重载 ## 重写与重载
- 覆盖（Override）存在于继承体系中，指子类实现了一个与父类在方法声明上完全相同的一个方法； - 重写（Override）存在于继承体系中，指子类实现了一个与父类在方法声明上完全相同的一个方法；
- 重载（Overload）存在于同一个类中，指一个方法与已经存在的方法名称上相同，但是参数类型、个数、顺序至少有一个不同。应该注意的是，返回值不同，其它都相同不算是重载。 - 重载（Overload）存在于同一个类中，指一个方法与已经存在的方法名称上相同，但是参数类型、个数、顺序至少有一个不同。应该注意的是，返回值不同，其它都相同不算是重载。
@ -724,7 +725,7 @@ ToStringExample@4554617c
**1. cloneable** **1. cloneable**
clone() 是 Object 的受保护方法，这意味着，如果一个类不显式去覆盖 clone() 就没有这个方法。 clone() 是 Object 的 protect 方法，它不是 public，一个类不显式去重写 clone()，其它类就不能直接去调用该类实例的 clone() 方法。
```java ```java
public class CloneExample { public class CloneExample {
@ -738,7 +739,7 @@ CloneExample e1 = new CloneExample();
// CloneExample e2 = e1.clone(); // 'clone()' has protected access in 'java.lang.Object' // CloneExample e2 = e1.clone(); // 'clone()' has protected access in 'java.lang.Object'
``` ```
接下来覆盖 Object 的 clone() 得到以下实现： 接下来重写 Object 的 clone() 得到以下实现：
```java ```java
public class CloneExample { public class CloneExample {
@ -1106,7 +1107,9 @@ Reflection is powerful, but should not be used indiscriminately. If it is possib
- **Security Restrictions** : Reflection requires a runtime permission which may not be present when running under a security manager. This is in an important consideration for code which has to run in a restricted security context, such as in an Applet. - **Security Restrictions** : Reflection requires a runtime permission which may not be present when running under a security manager. This is in an important consideration for code which has to run in a restricted security context, such as in an Applet.
- **Exposure of Internals** :Since reflection allows code to perform operations that would be illegal in non-reflective code, such as accessing private fields and methods, the use of reflection can result in unexpected side-effects, which may render code dysfunctional and may destroy portability. Reflective code breaks abstractions and therefore may change behavior with upgrades of the platform. - **Exposure of Internals** :Since reflection allows code to perform operations that would be illegal in non-reflective code, such as accessing private fields and methods, the use of reflection can result in unexpected side-effects, which may render code dysfunctional and may destroy portability. Reflective code breaks abstractions and therefore may change behavior with upgrades of the platform.
> [Trail: The Reflection API](https://docs.oracle.com/javase/tutorial/reflect/index.html) </br> [深入解析 Java 反射（1）- 基础](http://www.sczyh30.com/posts/Java/java-reflection-1/)
- [Trail: The Reflection API](https://docs.oracle.com/javase/tutorial/reflect/index.html)
- [深入解析 Java 反射（1）- 基础](http://www.sczyh30.com/posts/Java/java-reflection-1/)
# 八、异常 # 八、异常
@ -1117,7 +1120,8 @@ Throwable 可以用来表示任何可以作为异常抛出的类，分为两种
<div align="center"> <img src="../pics//PPjwP.png" width="600"/> </div><br> <div align="center"> <img src="../pics//PPjwP.png" width="600"/> </div><br>
> [Java 入门之异常处理](https://www.tianmaying.com/tutorial/Java-Exception) </br> [Java 异常的面试问题及答案 -Part 1](http://www.importnew.com/7383.html) - [Java 入门之异常处理](https://www.tianmaying.com/tutorial/Java-Exception)
- [Java 异常的面试问题及答案 -Part 1](http://www.importnew.com/7383.html)
# 九、泛型 # 九、泛型
@ -1130,13 +1134,14 @@ public class Box<T> {
} }
``` ```
> [Java 泛型详解](http://www.importnew.com/24029.html)</br>[10 道 Java 泛型面试题](https://cloud.tencent.com/developer/article/1033693) - [Java 泛型详解](http://www.importnew.com/24029.html)
- [10 道 Java 泛型面试题](https://cloud.tencent.com/developer/article/1033693)
# 十、注解 # 十、注解
Java 注解是附加在代码中的一些元信息，用于一些工具在编译、运行时进行解析和使用，起到说明、配置的功能。注解不会也不能影响代码的实际逻辑，仅仅起到辅助性的作用。 Java 注解是附加在代码中的一些元信息，用于一些工具在编译、运行时进行解析和使用，起到说明、配置的功能。注解不会也不能影响代码的实际逻辑，仅仅起到辅助性的作用。
> [注解 Annotation 实现原理与自定义注解例子](https://www.cnblogs.com/acm-bingzi/p/javaAnnotation.html) [注解 Annotation 实现原理与自定义注解例子](https://www.cnblogs.com/acm-bingzi/p/javaAnnotation.html)
# 十一、特性 # 十一、特性
@ -1165,7 +1170,8 @@ Java 注解是附加在代码中的一些元信息，用于一些工具在编译
7. Binary Literals, Underscore in literals 7. Binary Literals, Underscore in literals
8. Diamond Syntax 8. Diamond Syntax
> [Difference between Java 1.8 and Java 1.7?](http://www.selfgrowth.com/articles/difference-between-java-18-and-java-17)</br> [Java 8 特性 ](http://www.importnew.com/19345.html) - [Difference between Java 1.8 and Java 1.7?](http://www.selfgrowth.com/articles/difference-between-java-18-and-java-17)
- [Java 8 特性](http://www.importnew.com/19345.html)
## Java 与 C++ 的区别 ## Java 与 C++ 的区别
@ -1185,7 +1191,7 @@ Java 是纯粹的面向对象语言，所有的对象都继承自 java.lang.Obje
| Java has built-in support for documentation comments (`/** ... */`); therefore, Java source files can contain their own documentation, which is read by a separate tool usually `javadoc` and reformatted into HTML. This helps keeping documentation maintained in easy way. | C++ does not support documentation comments. | | Java has built-in support for documentation comments (`/** ... */`); therefore, Java source files can contain their own documentation, which is read by a separate tool usually `javadoc` and reformatted into HTML. This helps keeping documentation maintained in easy way. | C++ does not support documentation comments. |
| Java is interpreted for the most part and hence platform independent. | C++ generates object code and the same code may not run on different platforms. | | Java is interpreted for the most part and hence platform independent. | C++ generates object code and the same code may not run on different platforms. |
> [What are the main differences between Java and C++?](http://cs-fundamentals.com/tech-interview/java/differences-between-java-and-cpp.php) [What are the main differences between Java and C++?](http://cs-fundamentals.com/tech-interview/java/differences-between-java-and-cpp.php)
## JRE or JDK ## JRE or JDK