INTRODUCTION TO JAVA

• ORIGIN OF JAVA (Conceived Java at Sun Microsystems (1991))


  
  

  • James Gosling
  • Patrick Naughton
  • Chris Warth
  • Ed Frank
  • Mike Sheridan
• ORIGIN OF JAVA

  called “Oak” but was renamed “Java” in 1995.
• ORIGIN OF JAVA(1)

  object-oriented programming language developed by James Gosling.
• ORIGIN OF JAVA(2)

  Java is intended to be compiled into a bytecode, which a Java Virtual Machine then runs.
• 1991


  James Gosling, Mike Sheridan, and Patrick Naughton started a project to create the Java language.
• ORIGIN OF JAVA

  Oak → Green → Java (type of coffee from Indonesia).
• ORIGIN OF JAVA

  Gosling used syntax similar to C/C++.
• ORIGIN OF JAVA

  1996 – Sun Microsystems released Java 1.0.
• ORIGIN OF JAVA

  Web browsers started supporting Java, making it popular.
• Java 2 came out with different versions for various platforms:

  J2EE – servers → Java EE

  J2ME – mobiles → Java ME

  J2SE – desktops → Java SE
• FEATURES OF JAVA

  • Platform-Independent
  • Object-oriented Language
  • Fast
  • Secure
  • Rich Standard Library
• Platform-Independent 


  programs in Java can run on any device or platform that has a Java Virtual Machine installed.

  “Write Once, Run Anywhere” (WORA) principle
• Object-oriented Language 


  supports concepts such as encapsulation, inheritance, and polymorphism, which makes it easier to design
• Fast 


  relatively fast language due to its use of a Just-In-Time (JIT) compiler.
• Secure 


  provides a robust security model.
• Rich Standard Library 


  comprehensive Standard Library (Java API) provides a wide range of pre-built classes and packages.
• JAVA

  • (Platform Independence) Platform - independent
  • (Memory Management) Automatic memory management (garbage collection)
  • (Object-Oriented) More strictly
  • (Security) Built-in security features
• C++

  • (Platform Independence) Need to be compiled separately
  • (Memory Management) Manual memory management
• JDK (Java Development Kit)


  comprehensive software development kit that includes tools and resources needed to develop, compile, and run Java applications.
• JDK (Java Development Kit) COMPONENTS:

  Compiler (javac)

  Java Virtual Machine (JVM)

  Java Runtime Environment (JRE)

  Development Tools
• Compiler (javac) 


  Translates Java source code into bytecode.
• Java Virtual Machine (JVM) 


  Executes Java bytecode.
• Java Runtime Environment (JRE) 


  Provides libraries, Java class libraries, and other files necessary for running Java applications.
• Development Tools 


  Debuggers, profilers, and other utilities.
• JAVA CODE

  Java Program → Java Compiler → Java Byte Code → Java Interpreter → Machine Code
• SAMPLE JAVA CODE

  public class Hello {

  public static void main(String[] args) {

  System.out.println("Hello World");

  }

  }
• JAVA OUTPUT


  In Java, to send output to standard output we can simply use

  System.out.println(); or System.out.print();
• print()


  It prints string inside the quotes.
• println() 


  It prints string inside the quotes similar like print() method. Then the cursor moves to the beginning of the next line.
• JAVA COMMENT


  can be used to explain Java code, and to make it more readable.
• Single Line Comment


  start with two forward slashes (//).
• Multi-line comments


  start with /* and end with */.