Java Programming Language PDF

JAVA Mobile application – most andoid app are written or use Java as language - high-level, class-based, object-oriented programming language. Big...

JAVA Mobile application – most andoid app are written or use Java as language - high-level, class-based, object-oriented programming language. Big data technologies - like Apache Hadoop, Apache - general-purpose programming language Spark. - "write once, run anywhere" (WORA). Scientific appliances - data processing, mathematical - by James Gosling, Mike Sheridan, and Patrick calculations, and simulations. Naughton at Sun Microsystems in 1991 - initially called "Oak" Gaming - used in developing 2D and 3D games, as well as mobile games. MILESTONE OF JAVA Cloud computing - like AWS, Google Cloud, and Azure 1991 - was initiated by James Gosling and the Green for developing scalable and distributed systems. Team at Sun Microsystems (originally designed for interactive television) 1995 – Officially launched Java 1.0 JAVA SYNTAX AND STRUCTURE 1997 – JDK 1.1 released 1999 – released of J2SE 1.2 , J2EE and J2ME public: The method is accessible from outside the class. 2004 – released of Java 5.0 (JS2E 1.5) static: Allows the method to run without creating an instance of the class. 2006 – released under General public license, making it free and open-source software void: The method does not return any value. 2014 - Java 8 features like lambda expressions, Stream String[] args: Command-line arguments passed to the API program. 2017 – announced that java would switch to a new Variable – Act as container to store data release cadence, new version every 6 months - int Present Java – used in wed development, mobile - double applicaion and large-scale enterpricec systems. - string Used for: Initialization – Assigning initial value to a variale - mobile app (andriods) - int age= - desktop app - string name = - web app - web servers and app servers 2 primary data types - games - Primative data types - database connection - Reference data types REAL WORLD APPLICATION Primative data Types Web application - used for building server-side - Btye - 1 byte small numbers applications. - Short – 2 bytes slightly larger no. - Frameworks like Spring, Hibernate, and Struts - Int: - 4 bytes integer type - Long – 8 bytes larger integer value Enterprise application - specifically designed for - Float - 4 bytes single-precision floating point building distributed, multi-tiered, transactional - Double – 8 bytes decimal values applications - Char - 2bytes sinle unicode character - Boolean – 1 bit true or flase Reference Data Type Conditional statement - Include classes, interfaces, arrays, string, and If statement – if the condition is true , simplest decision custom classes making stat. - They store references to object rather than the else if ladder – first true condition’s block gets executed, object itself the rest are skipped. Local variables – Accessible only within that method Looping statement Instance Variable (Fields) – declared within the class While loop – executes as long as condition is true but outside any method Do-while loop – block of code executed because it is Class variables (static fields) - declared within the static check after the block is executed keyword and shared across all instances of all class For loop – used when you know how many times you Java operators – perform operations on variables want to loop - Arithmetic operators o Addition(+) , Subtraction(-), Multiplication(*), Division(/), Modulus CODE EXAMPLE: (%) - Assignment operators import java.util.Scanner; o Use to assign values to variables (=) public class Main { - Compound assignment operators public static void main(String[] args) { o Operation with assignment Scanner scanner = new Scanner (System.in); ▪ +=, -=, *+, /= System.out.print("Enter your age: "); - Comparison operators int age = scanner.nextInt(); o To compare, Boolean result (true or false) if (age >= 18) { ▪ Equal to (==), Not equal to (!=), System.out.println("You are eligible to vote."); - Logical operators }else { o Combining multiple condition, Boolean System.out.println("You are not eligible to result vote."); ▪ AND && - Returns true if both } stat is true } } ▪ OR || - True if one condition is true ▪ NOT ! – inverts the Boolean value - Increment or Decrement o To increase and decrease ▪ Increment ++ ▪ Decrement – Conditional Statement – flow of execution to be controlled within a program - Making decisions, repeating tasks or branching paths Java control statement - Decision-making statement - Looping (iteration) statement