Summary Java Programming

Introduction to Java
Programming Language
Classes and Objects

 A class is a blueprint for creating objects in Java
 An object is an instance of a class
Instance Variables

 Variables defined in a class, but not declared
as static are instance variables

 Each object of a class has its own copy of
instance variables
Arrays in Java

 A single-dimensional array holds several values of
the same type
 A multi-dimensional array is an array of arrays
Array Memory Allocation

 Array memory is allocated in a contiguous block
this Keyword and Method Parameters

 this keyword is a reference to the current object

 Method parameters are local variables
Java Class and Compilation Process

 Java source code ( .java ) is compiled into
bytecode ( .class )

,  Bytecode is executed by the Java Virtual Machine
(JVM)
Package and Access Modifiers

 Access modifiers determine the access level of
fields and methods
 public , private , protected , and the default
(package-private) access modifier
Java Namespaces and Package
Management

 Packages provide a way to organize and access
classes
 Packages also help avoid naming conflicts
Java Hello World Example and Entry Point

 public static void main(String[] args) is
the entry point for a Java application
Abstract Classes and Abstraction

 Abstract classes cannot be instantiated
 Abstraction is the process of hiding
implementation details
Final Keyword

 The final keyword can be applied to variables,
methods, and classes
 A final variable cannot be reassigned

 A final method cannot be overridden