Java_Programming

Java is a popular high-level programming language that was developed by James Gosling at Sun Microsystems. It is a general purpose programming language used for developing mobile, web, desktop and server-side applications.

Features:

• Platform independence

Java programs can run on any operating system or hardware platform as long as there is a Java Virtual Machine(JVM) installed.

• Object-oriented programming.

Java is based on the concepts of objects, which can contain both data and methods to manipulate that data.

• Security.

Java has a strong emphasis on security, making it a popular choice for developing web applications and mobile aplications.

• Versatility.

Java can be used for a wide range of applications, including desktop, web, and mobile applications, as well as embedded systems and server-side applications.

Java Syntax

Java Syntax is a set of rules that we follow when we are writing programs in java programming language. We use words like class and public to tell the computer what we want to do and symbols like curly braces {} and parantheses () to group things together and make our program easier to read.

Each Java language construct has its own unique syntax that specifies how it is written and used in java program.By following the correct syntax for each costruct, we can ensure that our java programs are correct and functional.

Class definition Syntax

A class is declared using the class keyword followed by the name of the class, and then the body enclosed in curly braces.

public class Myclass {
  //body of the class
}

The class body is where the properties and behaviour of a class is defined.

Variable declaration syntax

The syntax for defining properties in a class is to declare variables inside the class body using access modifier such as public or private followed by a variable type and name. Here is an example:

public class Myclass {
  public int x; //variable x declared with access modifier public and data type int
  private String name; //Property name declared with access modifier private and data type String
}

Java Collection Interface

The Collection interface is the root interface of the java collection framework.The collection interface is implemented in indirectly by the List, Queue and Set subinterfaces. The arraylist, linkedlist classes implement the list interface which is a sub-interface of the collection interface.

Methods of the collection interface

• add()
• size()
• remove()
• addAll()
• removeAll()
• clear()
• iterator()

*** Java List *** Elements are stored and accessed sequentially. It extends the collection interace. Classes that Implement the functionalities of the list interface are:

• ArrayList
• LinkedList
• Vector
• Stack

*We must import java.util.List package inorder to use list

//ArrayList Implementation of List
List<String> items = new ArrayList<>();

//LinkedList Implementation of list
List<String> numbers = new LinkedList<>();

Methods of the list Interface

• add()
• addAll()
• get()
• iterator()
• set()
• remove()
• removeAll()
• clear()
• size()
• toArray()
• contains()

Java List vs Set

• List can include duplicate elements. However, sets cannot have duplicate elements.
• Elements in list are sorted in some order. Elements in sets are stored in groups like a set in mathedmatics.

String processing

Methods of the String Class

String analysis

• Length.()
• isEmpty()
• indexOf()
• lastIndexOf()
• matches()

String comparison

• equals()
• equalsIgnoreCase()
• contentEquals()
• contains()
• startsWith()
• endsWith()
• compareTo()
• compareToIgnoreCase()

String transformation

• substring() - Returns the substring, starting with the specified index
• format() - Uses the passsed-in first argument as a template and inserts other arguments in the corresponding position of the template sequentially
• concat() - Works the same way as the arithmetic operator
• join()
• replace()
• replaceFirst()
• replaceAll()
• toLowerCase()
• toUpperCAse()
• split() - Breaks down the string into substrings, using the provided character as delimiter
• valueOf() - Transforms the values of primitive types to a string type

Reader and Writer Classes

Specializes in processing texts.