Programming Languages: Java and Javascript Quiz

International & Access Foundation Programmes

• Computer Science Semester II, Part 2, Java Basics
• Course presented by Nevan Bermingham

Important Information

• Students should create their own notes in addition to in-class ones
• Download class notes to use for lab work
• Download BlueJ (http://www.bluej.org/)

What is a Programming Language?

• "An artificial language used to write instructions that can be translated into machine language and then executed by a computer"
• Java is an example of a programming language
• A program is a list of instructions for a computer
• Programming languages are used to create programs controlling computer behavior
• A program is created using a programming language and compiled into an application

What is Java & Javascript?

• Java is a programming language used to create applications running on any computer (e.g., Windows, macOS)
• JavaScript is used to build applications within webpages by the browser (sometimes called an "applet")

Why do we use Javascript?

• HTML is static, remaining the same every time
• HTML only positions webpage elements
• JavaScript enables dynamic, user-interactive webpage elements (e.g., clocks, moving banners, games)

Why do we use Java & JavaScript?

• Java is simpler than most other languages
• Java and JavaScript are platform-independent, running on many computer types
• Java's design facilitated network use, ideal for internet applications
• Java prioritizes user and data security
• Java is freely available

Why Not Use English?

• Students should document observations from a provided picture
• Provide detailed descriptions of features/elements visible

What's a Compiler?

• A compiler application, working with the operating system, computers hardware, internet, keyboard, and mouse/screen, creates an application from Java Code
• The compiler makes the application
• This application can run on other computers

What Does a Compiler Do?

• A compiler transforms source code into a binary form known as object code
• This is often bytecode in Java
• The compiler links the code to libraries (e.g., standard java libraries)

Java Code is Compiled for an OS

• Java code is compiled for an operating system
• The compiler translates Java code to bytecode
• Java Virtual Machine (JVM) interprets the bytecode
• Code is run on the machine's hardware with assistance from storage, input/output, and network components

Where does Java Fit In?

• Java is among many important/popular programming languages (e.g., C++, Python)
• Presented in a timeline, with visual indicators noting dates of development

What Are Java Libraries?

• The Java Class Library is a collection of reusable functions used by Java applications at runtime
• Libraries, such as input/output, mathematical functions, graphics, file handling, and networking, depend heavily on the computer's platform

Compiling Code

• Compilers transform source code into a binary format—object code (bytecode in Java)
• Compilers link with standard Java libraries for essential functions (e.g., input/output)

Java Popularity

• Java is a highly popular programming language (data presented as a bar graph highlighting other languages of similar popularity)

Why Java?

• Java's "write once, run anywhere" capability simplifies code execution across varied computer platforms and operating systems
• Java is easily applicable in client-server web application development

These are FLOWCHARTS

• Flowcharts are pictorial representations of processes, which promotes understanding
• Flowcharts illustrate the logic of how a program works, using action boxes, decision boxes, start/end symbols, and connecting arrows
• This graphical representation displays the program's start, condition evaluation, action taken, input/output actions, and termination

Why use Flowcharts?

• Flowcharts are a visual, industry-standard documentation method
• They offer clear illustrations of programs, using common visual elements—facilitating understanding without complex technical terms

The Mathematics of Computing

• Boolean logic tests conditions in computer programs
• Binary is the fundamental language of computers (0s and 1s)
• Hexadecimal (base-16) is used instead of binary for more concise representation in computation

Boolean Logic

• Boolean algebra, originated in 1854 by George Boole, forms the basis of truth values (0 and 1), often represented as False(0) and True(1)
• Modern computers use Boole's system by employing microchips containing thousands of electronic switches arranged into logical "gates", such as the logical AND operation

Logical Operators

• Used to determine outcomes under specific conditions (e.g., rain and/or forecast)

'OR' Operator

• OR operator truth-table analysis

'AND' Operator

• AND operator truth-table analysis

NOT Expressions

• NOT statements are used for cases where an outcome is not a match (e.g., traffic light is not red)

Binary

• Computer counting is done in binary (0s and 1s)

Hexadecimal

• Hexadecimal (base-16) is a more concise representation of binary numbers
• Humans commonly use decimal counting

Hexadecimal (HEX)

• Hexadecimal (base 16) provides a more compact way to express binary values (0s and 1s)
• Conversion charts translate hexadecimal values into binary and decimal equivalents

Hexadecimal (HEX) & Binary

• Detailed table showing the conversion from hexadecimal (base-16) to binary (base-2)

Hexadecimal (HEX)

• Bytes are 8 bits
• In binary, ranges from 0000 0000 to 1111 1111
• The range in hexadecimal is 0x00 to 0xFF
• Decimal equivalent is from 0 to 255

HEX in Java

• Java uses hexadecimal (HEX) for color selection (e.g., Red 0xFF0000, Green 0x00FF00)

Terminology Review

• Browsers display HTML content
• Operating systems execute computer programs
• Compilers transform code into executable applications
• HTML is a language that structures and lays out webpages

Further Reading

• Java books and websites (e.g. "Java for Dummies," "Java Made Easy")
• Online resources for further Java study