programming in java

CHAPTER SUMMARY

1. A computer is an electronic device that stores and processes data.

2. A computer includes both hardware and software.

3. Hardware is the physical aspect of the computer that can be seen.

4. Computer programs, known as software, are the invisible instructions that control the

hardware and make it perform tasks.

5. Computer programming is the writing of instructions (i.e., code) for computers to

perform.

6. The central processing unit (CPU) is a computer’s brain. It retrieves instructions from

memory and executes them.

7. Computers use zeros and ones because digital devices have two stable states, referred

to by convention as zero and one.

8. A bit is a binary digit 0 or 1.

9. A byte is a sequence of 8 bits.

10. A kilobyte is about 1000 bytes, a megabyte about 1 million bytes, a gigabyte about 1

billion bytes, and a terabyte about 1000 gigabytes.

11. Memory stores data and program instructions for the CPU

12. A memory unit is an ordered sequence of bytes.

13. Memory is volatile, because information is lost when the power is turned off.

Programs and data are permanently stored on storage devices and are moved to memory

when the computer actually uses them.

15. The machine language is a set of primitive instructions built into every computer.

16. Assembly language is a low-level programming language in which a mnemonic is

used to represent each machine-language instruction.

17. High-level languages are English-like and easy to learn and program.

18. A program written in a high-level language is called a source program.

19. A compiler is a software program that translates the source program into a machinelanguage

program.

20. The operating system (OS) is a program that manages and controls a computer’s

activities.

21. Java is platform independent, meaning that you can write a program once and run it

anywhere.

22. Java programs can be embedded in HTML pages and downloaded by Web browsers

to bring live animation and interaction to Web clients.

23. Java source files end with the .java extension.

24. Every class is compiled into a separate bytecode file that has the same name as the

class and ends with the .class extension.

25. To compile a Java source-code file from the command line, use the javac command.

26. To run a Java class from the command line, use the java command.

27. Every Java program is a set of class definitions. The keyword class introduces a

class definition. The contents of the class are included in a block.

28. A block begins with an opening brace ({) and ends with a closing brace (}). Methods

are contained in a class.

29. A Java program must have a main method. The main method is the entry point where

the program starts when it is executed.

30. Every statement in Java ends with a semicolon (;), known as the statement terminator.

31. Reserved words, or keywords, have a specific meaning to the compiler and cannot be

used for other purposes in the program.

32. In Java, comments are preceded by two slashes (//) on a line, called a line comment,

or enclosed between /* and */ on one or several lines, called a block comment.

33. Java source programs are case sensitive.

34. There are two types of import statements: specific import and wildcard import. The

specific import specifies a single class in the import statement. The wildcard import

imports all the classes in a package.