Introduction to Java Programming - Session 1 PDF

Here's the conversion of the provided text and images into a structured markdown format. # School of Computing and Information Systems MT103- Computer Programming with * Session 1 * Topic: Introduction to Java programming Botswana Accountancy College Year of Study: 1 Programmes: Computer Systems...

Here's the conversion of the provided text and images into a structured markdown format. # School of Computing and Information Systems MT103- Computer Programming with * Session 1 * Topic: Introduction to Java programming Botswana Accountancy College Year of Study: 1 Programmes: Computer Systems Engineering, Mobile Technologies Botswana Accountancy College 2018 ## Objectives You will learn about programming language concepts, generations of programming languages, history of Java, the process of creating, compiling, and executing Java programs. ## Programming Language Concepts Before Java, students should try and answer the following questions: 1. What is a programming language? 2. Why are there so many programming languages? 3. What are the types of programming languages? 4. Does the world need new languages? ## Programming Language Concepts * English is a natural language. It has words, symbols, and grammatical rules. * A programming language also has words, symbols, and rules of grammar. * The grammatical rules are called syntax. * Each programming language has a different set of syntax rules. ## Programming Language Concepts * A programming language is a set of rules that provides a way of telling a computer what operations to perform. * A programming language is a set of rules for communicating an algorithm. * It provides a linguistic framework for describing computations. ## Programming Language Concepts * Why does some people speak French? * Programming languages have evolved over time as better ways have been developed to design them. * First programming languages were developed in the 1950s * Since then thousands of languages have been developed. * Different programming languages are designed for different types of programs. ## Programming Language Types **1. First Generation Languages** I. Machine language * Operation code – such as addition or subtraction. * Operands – that identify the data to be processed. * Machine language is machine dependent as it is the only language the computer can understand. * Very efficient code but very difficult to write. ## Programming Language Types **2. Second Generation Languages** i. Assembly languages * Symbolic operation codes replaced binary operation codes. * Assembly language programs needed to be “assembled” for execution by the computer. Each assembly language instruction is translated into one machine language instruction. * Very efficient code and easier to write. ## Programming Language Types **3. Third Generation Languages** i. Closer to English but included simple mathematical notation. * Programs written in source code which must be translated into machine language programs called object code. * The translation of source code to object code is accomplished by a machine language system program called a compiler. * Alternative to compilation is interpretation which is accomplished by a system program called an interpreter. * Common third-generation languages * FORTRAN * COBOL * C and C++ * Visual Basic ## Programming Language Types **4. Fourth Generation Languages** i. Programming-like systems aimed at simplifying the programmer's task of imparting instructions to a computer. ii. Many are associated with specific application packages. * Query Languages * Report Writers * Application Generators ## Programming Language Types **4. Fourth Generation Languages** i. Object-Oriented Languages: A language that expresses a computer problem as a series of objects a system contains, the behaviors of those objects, and how the objects interact with each other. i. Object: Any entity contained within a system. *Examples:* ii. A window on your screen. iii. A list of names you wish to organize. iv. An entity that is made up of individual parts. ii. Some popular examples: C++, Java, Smalltalk, Eiffel ## Programming Language Types **5. Fifth Generation Languages** i. Declarative languages ii. Functional(?): Lisp, Scheme, SML iii. Also called applicative iv. Everything is a function v. Logic: Prolog vi. Based on mathematical logic vii. Rule- or Constraint-based ## Java Java is; * a complete programming language developed by Sun Microsystems * Can be used to develop either web based or stand-alone software * Many pre-created code libraries available * For more complex and powerful programs * Forth generation language * Platform independent language – Java for everything ## Java * A Rich Subset of the Java Language ## Java: History * Computers of the past Image: Black and white photo of a large room filled with computing equipment and several people are working on it. ## Java: History (2) * The invention of the microprocessor revolutionized computers Image 1: There is an Intel Microprocessor Image 2: There is Commodore Pet microcomputer ## Java: History (3) * It was believed that the logical next step for microprocessors was to have them run intelligent Image: Depicts a cutaway illustration of a modern "smart" home, showing networked devices with icons representing functions like security, climate control, communication and entertainment. ## Java History (4) * Sun Microsystems funded an internal research project “Green” to investigate this opportunity. * Result: A programming language called “Oak” Image: Man with glasses and full beard wearing a patterned shirt ## Java History (5) * Problem: There was already a programming language called Oak. * The “Green” team met at a local coffee shop to come up with another name... Image 1: Photo an aisle of chairs and tables inside a caffe shop Image 2: The word JAVA and a graphic are shown ## Java: History (6) * The concept of intelligent devices did not catch on. * Project Green and work on the Java language was nearly canceled. Image: Cartoon of a person running from an outdated computer ## Java: History (7) * The popularity of the Internet resulted in Sun's re-focusing of Java on computers. * Prior to the advent of Java, web pages allowed you to download only text and images. Image: Diagram illustrating how a home computer used to access resources from a distant server ## Java: History (8) * Java enabled web browsers allowed for the downloading of programs (Applets). * Java is still used in this context today. * Facebook (older version) * Hotmail (older version) Image: Diagram illustrating how a home computer used to access programs from a distant server Java version of the Game of Life: [http://www.bitstorm.org/gameoflife/](http://www.bitstorm.org/gameoflife/) Online checkers: [http://www.darkfish.com/checkers/index.html](http://www.darkfish.com/checkers/index.html) ## Java: Write Once, Run Anywhere * Consequence of Java's history: platform-independence **Image representation:** Diagram illustrating a Mac and Windows user both accessing byte code from a Unix server. ## Java: Write Once, Run Anywhere (2) * But Java can also create standard (non-web-based) programs Image 1: A screenshot from the Java version of the game Dungeon Master. Image 2: A poster advertising Kung Fu panda ## Java: Write Once, Run Anywhere (3) * Java has been used by large and reputable companies to create serious stand-alone applications. * Example: * Eclipse: started as a programming environment created by IBM for developing Java programs. The program Eclipse was ... Image: A screenshot showing a diagram editor within the Eclipse development environment. 1 For more information: [http://www.eclipse.org/downloads/](http://www.eclipse.org/downloads/) ## Java: Features 1. Java is Object Oriented 2. Use ‘Classes' to define problem characteristics. 3. Each class instance or occurrence is represented by an 'Object' from that class category. 4. Java objects communicate to solve a problem. 5. This problem solution space is called a Java ‘Application' or program. ## Java: benefits 1. Object Oriented – has a very rich collection of Reusable classes called (API) or Application Programming Interface. 2. Usable across different computer environments- Portable. 3. Secure features for robust Applications. 4. Free downloads (No need to buy usage licenses). 5. Widely supported by the community and Sun Microsystems Image: Diagram illustrating how computer program has to be compiled with different compilers for each system to create an executable ## A High-Level View Of Translating/Executing Java Programs Stage 1: Compilation Image: Translation of a Java program to Java bytecode ## A High-Level View Of Translating/Executing Java Programs (2) Stage 2: Interpreting and executing the byte code Image: Java bytecode is interpreted according to the system and produces system-specific code for execution ## Which Java? * Java 6+ JDK (Java Development Kit), Standard Edition includes: * JDK (Java development kit) – for developing Java software (creating Java programs). * JRE (Java Runtime environment) – only good for running pre-created Java programs. * Java Plug-in – a special version of the JRE designed to run through web browsers. * Current version is 1.8.0. a.k.a. Java1.8 or JDK8. * An enterprise version called J2EE (Java-Two Enterprise Edition) is also available for advanced programmers. [http://java.sun.com/javase/downloads/index.jsp](http://java.sun.com/javase/downloads/index.jsp) ## Smallest Compilable And Executable Java Program The name of the online example is: `HelloWorld.java` *(Important note: file name matches the word after the keyword 'class')* 1. Create the program by typing it into a text editor, and save it as `HelloWorld.java`. ## Smallest Compilable And Executable Java Program The name of the online example is: `HelloWorld.java` *(Important note: file name matches the word after the keyword 'class')* 2. Compile it by typing at the command-line: `javac HelloWorld.java..` *(or click the Compile button in JGrasp)* ## Smallest Compilable And Executable Java Program The name of the online example is: `HelloWorld.java` *(Important note: file name matches the word after the keyword 'class')* 3. Execute it by typing at the command-line: `java HelloWorld...` Diagram of how a Java programmer would compile and run programs ## Compiling The Smallest Java Program ```java HelloWorld.java public class HelloWorld { public static void main (String[] args) { } } ``` Image: Code is compiled into Java byte code ## Running The Smallest Java Program **Image:** Java byte code is translated into system specific code for execution. ## Running The Java Compiler At Home * After installing Java you will need to indicate to the operating system where the java compiler has been installed (‘setting the path'). * For details of how to set your path variable for your particular operating system try the Sun or Java website. * Example of how to set the path in Windows: * [http://java.sun.com/j2se/1.4.2/install-windows.html](http://java.sun.com/j2se/1.4.2/install-windows.html) *(see step 5)* ## Documentation / Comments Multi-line documentation ```java /* Start of documentation */ End of documentation ``` Documentation for a single line ```java //Everything until the end of the line is a comment ``` ## Review: What Should You Document * Program (or that portion of the program) author * What does the program as a whole do e.g., tax program. * What are the specific features of the program e.g., it calculates personal or small business tax. * What are its limitations e.g., it only follows Botswana tax laws and cannot be used in the SADC. In Botswana, it doesn't calculate taxes for organizations with yearly gross earnings over P1 billion. * What is the version of the program * If you don't use numbers for the different versions of your program then consider using dates (tie versions with program features). ## Important Note * Each Java instruction must be followed by a semi-colon! | General format | Examples | | :------------- | :----------------------- | | Instruction1; | int num = 0; | | Instruction2; | System.out.println(num); | | Instruction3; | : | | : | : | ## Java Output * **Format:** ```java System.out.print(<string or variable name one> + <string or variable name two..); OR System.out.println(<string or variable name one> + <string or variable name two..); ``` * **Examples (Program called "OutputExample1.java")** ```java public class OutputExample1 { public static void main(String[] args) { int num = 123; // More on this shortly System.out.println("Good-night Robbie!"); System.out.print(num); System.out.println("num="+num); } } ``` ## Output : Some Escape Sequences For Formatting | Escape sequence | Description | | :-------------- | :------------- | | \t | Horizontal tab | | \r | Carriage return | | \n | New line | | \" | Double quote | | \\\ | Backslash | ## Example Formatting Codes * Name of the example: FormattingExample.java ```java public class FormattingExample { public static void main (String [] args) { System.out.print("lol\tz\n"); System.out.println("hello\rworld"); System.out.println("\"Geek\" talk slash (\\) com"); } } ``` ## After This Section You Should Now Know 1. Programming language concepts and types 2. How Java was developed and the impact of it’s roots on the language 3. Different Java versions 4. The basic structure required in creating a simple Java program as well as how to compile and run programs 5. How to document a Java program