3.6. StringsConceptually, Java strings are sequences of Unicode characters(Java的字符串是一个Unicode序列). For example, the string "Java\u2122" consists of the five Unicode characters J, a, v, a, and ?. Java does not have a built-in string type(Java没有内置的…

1.2. The Java "White Paper" BuzzwordsThe authors of Java have written an influential White Paper that explains their design goals and accomplishments. They also published a shorter summary that is organized along the following 11 buzzwords:1. Si…

4.7. PackagesJava allows you to group classes in a collection called a package. Packages are convenient for organizing your work and for separating your work from code libraries provided by others.The standard Java library is distributed over a numbe…

3.10. ArraysAn array is a data structure that stores a collection of values of the same type. You access each individual value through an integer index. For example, if a is an array of integers, then a[i] is the ith integer in the array.Declare an a…

3.8. Control FlowJava, like any programming language, supports both conditional statements and loops to determine control flow. We will start with the conditional statements, then move on to loops, to end with the somewhat cumbersome switch statement…

3.3. Data TypesJava is a strongly typed language(强类型语音). This means that every variable must have a declared type(每个变量都必须声明类型). There are eight primitive types in Java(Java有8种原始类型). Four of them are integer types; two are floatingpoint number types;…

Let’s look more closely at one of the simplest Java programs you can have—one that simply prints a message to console: public class FirstSample { public static void main(String[] args) { System.out.println("We will not use 'Hello, World!'"); } }…

5.1. Classes, Superclasses, and SubclassesLet's return to the Employee class that we discussed in the previous chapter. Suppose (alas) you work for a company at which managers are treated differently from other employees. Managers are, of course, jus…

4.10. Class Design HintsWithout trying to be comprehensive or tedious, we want to end this chapter with some hints that will make your classes more acceptable in well-mannered OOP circles. 1. Always keep data private. This is first and foremost; doin…

4.6. Object ConstructionYou have seen how to write simple constructors that define the initial state of your objects. However, since object construction is so important, Java offers quite a variety of mechanisms for writing constructors. We go over t…