Introduction to Computer Science Concepts
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Questions and Answers

Java was first named Oak before it was renamed to Java.

True

Java applications require a web browser to run.

False

Java was developed by the Red Team at Sun Microsystems.

False

The HotJava browser was demonstrated in 1995.

<p>True</p> Signup and view all the answers

Java's security model for applets is relaxed compared to applications.

<p>False</p> Signup and view all the answers

Java is considered cross-platform because it can run on different operating systems.

<p>True</p> Signup and view all the answers

Computer programmers have no role in implementing programs.

<p>False</p> Signup and view all the answers

In addition to word processing, computers can perform functions such as gaming and databases.

<p>True</p> Signup and view all the answers

Main memory is also known as hard disk storage.

<p>False</p> Signup and view all the answers

The central processing unit (CPU) is categorized as a software component.

<p>False</p> Signup and view all the answers

A byte consists of eight bits that can be either on or off.

<p>True</p> Signup and view all the answers

RAM is persistent memory, meaning its contents are retained when the computer is turned off.

<p>False</p> Signup and view all the answers

The mathematical procedures in a computer program do not need to be correct for the program to function.

<p>False</p> Signup and view all the answers

Input and Output devices are considered major hardware components of a computer.

<p>True</p> Signup and view all the answers

The layout of programming statements is a critical aspect of program design.

<p>True</p> Signup and view all the answers

Each byte in RAM is assigned a unique number known as a port.

<p>False</p> Signup and view all the answers

Application software includes spreadsheets and games.

<p>True</p> Signup and view all the answers

An algorithm consists of random steps to complete a task.

<p>False</p> Signup and view all the answers

Machine language is expressed in a decimal system.

<p>False</p> Signup and view all the answers

The first high-level programming language was called assembler.

<p>True</p> Signup and view all the answers

Each CPU has its own unique machine language.

<p>True</p> Signup and view all the answers

High level programming languages are processor dependent.

<p>False</p> Signup and view all the answers

The binary numbering system is a base 10 system.

<p>False</p> Signup and view all the answers

Application software is unnecessary for a computer to function.

<p>True</p> Signup and view all the answers

Python is a common programming language mentioned in the list.

<p>True</p> Signup and view all the answers

In Java, key words are case sensitive and can be used as programmer-defined identifiers.

<p>False</p> Signup and view all the answers

Each Java statement must end with a semi-colon.

<p>False</p> Signup and view all the answers

A statement in Java is defined as a complete instruction that causes the computer to perform an action.

<p>True</p> Signup and view all the answers

Java supports three types of punctuation: commas, periods, and colons.

<p>False</p> Signup and view all the answers

Variables in Java can be created without a programmer-defined identifier.

<p>False</p> Signup and view all the answers

The keyword 'void' indicates that a method does not return any value in Java.

<p>True</p> Signup and view all the answers

The statement 'System.out.println(message);' is an example of a Java statement written on one line.

<p>False</p> Signup and view all the answers

A Java source file can be executed directly by the CPU.

<p>False</p> Signup and view all the answers

Files containing Java byte code have a .byte extension.

<p>False</p> Signup and view all the answers

The Java Virtual Machine (JVM) is often considered an interpreter.

<p>True</p> Signup and view all the answers

Portability in Java allows programs to run on various platforms without modification.

<p>True</p> Signup and view all the answers

Java requires recompilation for each CPU variation to ensure compatibility.

<p>False</p> Signup and view all the answers

Java byte code is the machine language specific to the Java CPU.

<p>False</p> Signup and view all the answers

The program development process in Java does not involve any text editing.

<p>False</p> Signup and view all the answers

Java programs can only be run on Windows and Unix operating systems.

<p>False</p> Signup and view all the answers

Software engineers are responsible for creating flow diagrams and program specifications.

<p>True</p> Signup and view all the answers

Most commercial software applications are typically developed by a single programmer.

<p>False</p> Signup and view all the answers

In object-oriented programming, attributes refer to the procedures that manipulate data.

<p>False</p> Signup and view all the answers

Data hiding in object-oriented programming means that data is kept secret from all objects.

<p>False</p> Signup and view all the answers

Encapsulation in object-oriented programming combines data and behavior within an object.

<p>True</p> Signup and view all the answers

The programming interface allows other objects to directly access an object's attributes.

<p>False</p> Signup and view all the answers

Software engineers use unique software tools specifically for testing programs.

<p>True</p> Signup and view all the answers

Pseudocode is a non-structured form of writing software specifications.

<p>False</p> Signup and view all the answers

Study Notes

Book Title and Edition

  • Starting Out With JavaTM, 7th Edition

Chapter 1 Title

  • Introduction to Computers and Java

Chapter Topics

  • Introduction
  • Why Program?
  • Computer Systems: Hardware and Software
  • Programming Languages
  • What Is a Program Made Of?
  • The Programming Process
  • Object-Oriented Programming

Java History

  • 1991 - Green Team started by Sun Microsystems (now owned by Oracle).
  • 7 handheld controller for multiple entertainment systems.
  • Need for a programming language to run on various devices.
  • Java (first named Oak) was developed for this.

Introduction

  • Java enabled web browser (HotJava) demonstrated at 1995 Sun World conference.
  • Java incorporated into Netscape shortly after.
  • Java is "cross-platform", meaning it can run on various computer operating systems.

Java Applications and Applets

  • Java programs can be of two types.
    • Applications
      • Stand-alone programs that run without a web browser.
      • Relaxed security model since user runs the program locally.
    • Applets
      • Small applications requiring a Java-enabled web browser to run.
      • Enhanced security model because user goes to web page for applet to run.

Why Program? (1 of 3)

  • Computers are tools that can be programmed to perform many functions: spreadsheets, databases, games, and word processing.
  • Computers are versatile because they can be programmed.
  • Computer programmers implement programs that perform these functions.

Why Program? (2 of 3)

  • Aspects of a computer program that need design:
    • The logical flow of the instructions.
    • The mathematical procedures.
    • The layout of programming statements.
    • The appearance of screens.
    • How information is presented to the user.
    • Program "user-friendliness."
    • Manuals, help systems and documentation.

Why Program? (3 of 3)

  • Programs must be analytically correct.
  • Programs rarely work correctly the first time.
  • Programmers must analyze, experiment, correct, and redesign programs continuously.
  • Programming languages have strict rules, known as syntax, that must be followed carefully.

Computer Systems: Hardware (1 of 2)

  • Computer hardware components are the physical parts of the computer.
  • Major hardware components are:
    • Central processing unit (CPU)
    • Main memory
    • Secondary storage devices
    • Input and output devices

Computer Systems: Hardware (2 of 2)

  • Diagram of various hardware components and their connections.

Computer Systems: Hardware - Main Memory (1 of 3)

  • Commonly known as random-access memory (RAM).
  • RAM contains currently running programs and data used by those programs.
  • RAM is divided into units called bytes.
  • A byte consists of eight bits that can be either on or off.

Computer Systems: Hardware - Main Memory (2 of 3)

  • A bit is either on or off: 1 = on, 0 = off.
  • Bits form patterns representing characters or numbers.
  • Each byte in memory has a unique number called an address.
  • RAM is volatile; its contents are erased when the computer is turned off.

Computer Systems: Hardware - Main Memory (3 of 3)

  • Main memory can be visualized as a column or row of cells.
  • A section of memory is called a byte.
  • A byte is made up of 8 bits.
  • A section of two or four bytes is often called a word.

Computer Systems: Hardware - Secondary Storage Devices

  • Secondary storage devices store information for longer periods (non-volatile).
  • Common devices: disk drive, external drive, CD drive, solid-state drive, USB drive, DVD drive

Computer Systems: Hardware - Input Devices

  • Input is any data collected from the outside world.
  • Data comes from input devices.
  • Common input devices: keyboard, mouse, scanner, digital camera

Computer Systems: Hardware - Output Devices

  • Output is any data sent to the outside world.
  • Data is displayed on output devices.
  • Common output devices: monitors, printers.
  • Some devices (e.g., disk drives) perform both input and output (I/O).

Computer Systems: Software

  • Software is the programs that run on a computer.
  • Two classifications: Operating Systems and Application Software.

Computer Systems: Software - Operating Systems (1 of 2)

  • Operating System is a set of programs that manages computer hardware devices and controls their processes.
  • Most modern operating systems are multitasking.

Computer Systems: Software - Operating Systems (2 of 2)

  • A multitasking operating system runs multiple programs at once.
  • Examples include Unix, Linux, Mac OS, Windows.
  • The technique used is called time-sharing.
  • The multitasking system allocates hardware resources and CPU time among all executing programs.

Computer Systems: Software - Application Software

  • Application software makes the computer useful to the user.
  • Application software provides a more specialized type of environment for the user.
  • Common application software include: spreadsheets, word processors, accounting software, tax software, games.

Programming Languages (1 of 5)

  • A program is a series of instructions a computer follows to perform a task.
  • Programming language is a special language used to write computer programs.
  • A computer program is a set of instructions that enables the computer to solve a problem or perform a task.
  • Collectively, these instructions form an algorithm.

Programming Languages (2 of 5)

  • An algorithm is a set of well-defined steps to complete a task.
  • Steps in an algorithm are performed sequentially.
  • A computer needs an algorithm written in machine language.
  • Machine language uses binary numbers.
  • The binary numbering system (base 2) has two digits: 0 and 1.

Programming Languages (3 of 5)

  • Binary numbers are encoded as machine language.
  • Each CPU has its own machine language.
    • Examples include Motorola 68000, Intel x86, ARM processors.
  • Example of a machine language instruction: 1011010000000101.

Programming Languages (4 of 5)

  • In the past, programmers wrote programs in machine language.
  • Programmers developed higher-level programming languages to make programming easier.
  • The first of these was assembler.
  • Assembler made things easier but was also processor-dependent.

Programming Languages (5 of 5)

  • High-level programming languages followed that were not processor-dependent.
  • Common programming languages (list).

Programming Languages - Common Language Elements

  • Common concepts used in programming languages:
    • Key words
    • Operators
    • Punctuation
    • Programmer-defined identifiers
    • Strict syntactic rules.

Programming Languages - Sample Program (1 of 2)

  • Sample Java code.

Programming Languages - Sample Program (2 of 2)

  • Key words in the sample program.
    • public, class, static, void
  • Key words are lower case (Java is case-sensitive).
  • Key words cannot be used as programmer-defined identifiers.

Programming Languages - Lines vs Statements

  • Lines vs. statements in source code.
  • System.out.println(message); is one statement written on two lines.
  • A statement is a complete Java instruction that makes the computer perform an action.

Programming Languages - Variables (1 of 3)

  • Data in a Java program is stored in memory.
  • Variable names represent memory locations.
  • Variables in Java are sometimes called fields.
  • Variables are created by the programmer who assigns an identifier (e.g., int hours = 40;).

Programming Languages - Variables (2 of 3)

  • Variables are simply names given to memory locations.

Programming Languages - Variables (3 of 3)

  • The Java Virtual Machine (JVM) decides where the value is placed in memory.
  • int length = 72; assigns the symbolic name length to memory location 0x003.

The Compiler and the Java Virtual Machine (1 of 4)

  • A programmer writes Java statements (source code).
  • A text editor is used to write and save source code files (with .java extension).
  • A compiler translates source code into an executable form.

The Compiler and the Java Virtual Machine (2 of 4)

  • A compiler is run with a source code file as input.
  • Syntax errors are programmer mistakes violating language rules.
  • Errors are discovered during compilation.
  • The compiler creates a file with translated instructions.

The Compiler and the Java Virtual Machine (3 of 4)

  • Most compilers turn source code into executable files that contain machine code.
  • A Java compiler turns a Java source file (.java) into a byte code file (.class).
  • Byte code is the machine language of the Java Virtual Machine (JVM).
  • Byte code cannot run directly on the CPU.

The Compiler and the Java Virtual Machine (4 of 4)

  • Byte code files have a .class extension.
  • The JVM emulates a microprocessor.
  • The JVM executes instructions as they're read.
  • The JVM is called an interpreter.
  • Java is an interpreted language.

Program Development Process

  • Diagram showing the process of creating, compiling, and running Java programs.
    • Text editor to write the source code.
    • Java compiler converts to byte code.
    • Java Virtual Machine to execute the byte code.

Portability (1 of 3)

  • Portable programs can run on different computers without modification.
  • Java byte code runs on the JVM; not on the specific CPU.

Portability (2 of 3)

  • Compilation is made for each type of CPU to achieve portability in most programming languages.
  • Java uses a JVM for each platform, so no recompilation is needed for different platforms.

Portability (3 of 3)

  • Diagram illustrating bytecode and associated Java Virtual Machines for different systems (e.g., Windows, Unix, Linux, Mac).

Java Versions

  • The Java Development Kit (JDK) is used to write Java programs.
  • Different JDK editions exist: Java SE, Java EE, Java ME.
  • JDKs are available for download at java.oracle.com.

Compiling a Java Program

  • The Java compiler is a command-line utility.
  • The command to compile a Java program is: javac filename.java.
  • The .java file extension is required.
  • Example: To compile Payroll.java use the command: javac Payroll.java

The Programming Process (1 of 2)

  • Four steps in the programming process
    1. Clearly define what the program is to do.
    2. Visualize program running on computer.
    3. Use design tools to create model of the program.
    4. Check the model for logical errors.

The Programming Process (2 of 2)

  • Continue the program design: 5. Enter the code and compile it. 6. Correct compilation errors. 7. Run program with test data. 8. Correct runtime errors. 9. Validate results of the program

Software Engineering (1 of 3)

  • Software engineering encompasses the entire process of creating computer software.
  • Software engineers perform tasks in complex software development projects (designing, writing, testing, debugging, documenting, modifying, and maintaining).

Software Engineering (2 of 3)

  • Software engineers develop: program specifications, screen output diagrams, diagrams of components and data flow, pseudocode, examples of input and output.

Software Engineering (3 of 3)

  • Special software is used for testing programs.
  • Large commercial software applications are usually developed by a team.
  • Program requirements are divided into subtasks for individuals or teams to handle.

Object-Oriented Programming (1 of 4)

  • Object-oriented programming is centered around creating objects rather than procedures.
  • Objects are a combination of data and procedures that manipulate that data.
  • Data in an object is known as attributes.
  • Procedures in an object are known as methods.

Object-Oriented Programming (2 of 4)

  • Diagram showing objects, attributes, and methods.

Object-Oriented Programming (3 of 4)

  • Object-oriented programming combines data and behavior through encapsulation.
  • Data hiding is where an object hides data from other objects in the program.
  • Only methods can directly manipulate object attributes.
  • Other objects manipulate attributes through methods.
  • This is the programming interface.

Object-Oriented Programming (4 of 4)

  • Diagram demonstrating how other objects access the object to interact with attributes and methods.

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Starting Out with Java 7th Edition PDF

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This quiz covers fundamental concepts in computer science, including Java programming, computer hardware, and memory types. It offers insights into the history and functionality of Java applications and key components of computer systems. Test your knowledge on various principles and definitions related to computing.

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