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The Java Tutorials have been written for JDK 8.Java教程是为JDK 8编写的。Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.本页中描述的示例和实践没有利用后续版本中引入的改进,并且可能使用不再可用的技术。
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.有关Java SE 9及其后续版本中更新的语言特性的摘要,请参阅Java语言更改。
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.有关所有JDK版本的新功能、增强功能以及已删除或不推荐的选项的信息,请参阅JDK发行说明。
Answers to Questions and Exercises: Variables
Answers to Questions
- The term "instance variable" is another name for non-static field.
- The term "class variable" is another name for static field.
- A local variable stores temporary state; it is declared inside a method.
- A variable declared within the opening and closing parenthesis of a method is called a parameter.
- What are the eight primitive data types supported by the Java programming language? byte, short, int, long, float, double, boolean, char
- Character strings are represented by the class java.lang.String.
- An array is a container object that holds a fixed number of values of a single type.
Answers to Exercises
- Create a small program that defines some fields. Try creating some illegal field names and see what kind of error the compiler produces. Use the naming rules and conventions as a guide.
There is no single correct answer here. Your results will vary depending on your code.
- In the program you created in Exercise 1, try leaving the fields uninitialized and print out their values. Try the same with a local variable and see what kind of compiler errors you can produce. Becoming familiar with common compiler errors will make it easier to recognize bugs in your code.
Again, there is no single correct answer for this exercise. Your results will vary depending on your code.