概念整理
在此将Thinking In Java中重要的知识点整理记录下来，其中很多都是不容易注意到的细节。
Java中基本数据类型在创建时都拥有初始值，具体如下：
| 类型名称 | 初始值 |
|---|---|
| boolean | false |
| char | ‘\u0000’ (null) |
| byte | (byte)0 |
| short | (short)0 |
| int | 0 |
| long | 0L |
| float | 0.0f |
| double | 0.0d |
作用域
类成员变量总是要赋予初值
方法签名
import
参数转型
private和final可以防止继承
The increment operator is one explanation for the name C++, implying “one step beyond C.”
In an early Java speech, Bill Joy (one of the Java creators), said that “Java=C++--” (C plus
plus minus minus), suggesting that Java is C++ with the unnecessary hard parts removed,
and therefore a much simpler language. As you progress in this book, you’ll see that many
parts are simpler, and yet in other ways Java isn’t much easier than C++.
print("" + x); // Shorthand for Integer.toString()
Notice the last example in main( ): you will sometimes see an empty String followed by a +
and a primitive as a way to perform the conversion without calling the more cumbersome
explicit method (Integer.toString( ), in this case).
