MyAssignmenthelp.Net : Learn Java At Your Tips

1
Introduction To JAVA
www.myassignmenthelp.net
2
Overview of JAVA

• Java is
• Platform independent programming language
• Similar to C in syntax
• Similar to Smalltalk in mental paradigm
• Pros also ubiquitous to net
• Cons interpreted, and still under development
  (moving target)

www.myassignmenthelp.net
3
How it works!
Java is independent only for one reason Only
depends on the Java Virtual Machine (JVM), code
is compiled to bytecode, which is interpreted by
the resident JVM, JIT (just in time) compilers
attempt to increase speed
www.myassignmenthelp.net
4
Java Features

• Well defined primitive data types int, float,
  double, char, etc.
• int 4 bytes 2,147,648, 2,147,483,647
• Control statements similar to C if-then-else,
  switch, while, for
• Interfaces
• Exceptions
• Concurrency
• Packages
• Name spaces
• Reflection
• Applet model
• Automatic type checking and garbage collection
• Simplifies pointers no directly accessible
  pointer to memory,
• Simplified network access,
• Multi-threading

www.myassignmenthelp.net
5
Applets, Servlets and Applications

• Applets
• Applet is designed to be embedded in a Web page,
  and run by a browser
• Applets run in a sandbox with numerous
  restrictions for example, they cant read files
  and then use the network
• Servlet
• A servlet is designed to be run by a web server
• Application
• An application is a conventional program

www.myassignmenthelp.net
6
The Java programming environment

• Java programming language specification
• Syntax of Java programs
• Defines different constructs and their semantics
• Java byte code Intermediate representation for
  Java programs
• Java compiler Transform Java programs into Java
  byte code
• Java interpreter Read programs written in Java
  byte code and execute them
• Java virtual machine Runtime system that
  provides various services to running programs
• Java programming environment Set of libraries
  that provide services such as GUI, data
  structures,etc.
• Java enabled browsers Browsers that include a
  JVM ability to load programs from remote hosts

www.myassignmenthelp.net
7
Java - Security

• Pointer denial - reduces chances of virulent
  programs corrupting host,
• Applets even more restricted -
• May not
• run local executables,
• Read or write to local file system,
• Communicate with any server other than the
  originating server.

www.myassignmenthelp.net
8
Object-Oriented

• Java supports OOD
• Polymorphism
• Inheritance
• Encapsulation
• Java programs contain nothing but definitions and
  instantiations of classes
• Everything is encapsulated in a class!

www.myassignmenthelp.net
9
Java Advantages

• Portable - Write Once, Run Anywhere
• Security has been well thought through
• Robust memory management
• Designed for network programming
• Multi-threaded (multiple simultaneous tasks)
• Dynamic extensible (loads of libraries)
• Classes stored in separate files
• Loaded only when needed

www.myassignmenthelp.net
10
Thank You
www.myassignmenthelp.net