4.5. Method ParametersLet us review the computer science terms that describe how parameters can be passed to a method (or a function) in a programming language. The term call by value(值调用) means that the method gets just the value that the caller pro…

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…

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…

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…

4.7. 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…

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…

4.4. Static Fields and MethodsIn all sample programs that you have seen, the main method is tagged with the static modifier. We are now ready to discuss the meaning of this modifier.4.4.1. Static Fields(静态域)If you define a field as static, then there…

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!'"); } }…

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…

3.6. 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…