Lecture 1: Introduction to java

Introduction to java:
Features or characteristics of java:
1.Simple:
2.Small:
3.Familiar:
4.Object Oriented:
Java’s whole structure is based on OOP Constructs. Java program is actually collection of objects. And each object contains its own set of data and set of methods/procedures/functions to operate object’s data.
Programmers/users can communicate with object through their methods or interface.
It’s make software development process very simple.
5.Platform independent / Architecture neutral:
Main aim of Java program can run on any hardware, Operating System, network that is simple to heterogeneous platform, truly portable than C/C++.
To achieve portability, java generates byte code that is intermediate code, instead of processor dependent code.
Example: Same java byte code can run on any platform.
Only platform specific JVM is required to execute byte code program. Hence each Operating System has their own JVM for example windows, Linux, Solaris etc. That is JVM is platform dependent but java language is platform independent.
Note:
Even .net languages are less portable than java that is weak point of .net languages.
6.Complied and Interpreted:
C / C++ follow only one stage of compilation of source code to object code. But java follows two stages:
Compilation:
Convert source code into byte code using java compiler.
Interpretation:
Convert the byte code into native machine code using java Interpreter / JIT compiler.
Java compiler written in java by Arthur Van Hoff and Interpreter written by James Gosling.
7.Multithreaded (Concurrent):
Single java program can execute multiple tasks simultaneously.
Same program having different modules can work on different thread simultaneously.
It provides high degree of interactivity which gives real effects.
8.Robust:
Using java we can design highly reliable software that it minimizes different types of software crash problems and leaks, memory bugs problem by removing pointer and dynamic memory management ability from java.
JVM is responsible for all types of system related operations. Programmer having no need to worry about these things.
Strongly typed language and very strict built-in internal checking.
Errors that are occurring at run time can be handled easily by Java. Java provides exception handling features to overcome many runtime problems like divide by zero, memory out of range, file not found etc.
Using their features user can properly exit or come out smoothly without program hanging.
9.Security:
Java provides strong security mechanism that runs java program under restricted environment.
It does not permit any viruses and unauthorized code. Hence java is so popular on Internet.
10.Distributed:
11.Native Interface:
Java program can call existing functions from C/C++ using JNI (Java Native Interface). This is called interoperability. But java does not provide strong interoperability as compared to .net.
12.High Performance:
13.Dynamic:
Java is more dynamic than C and C++.
In java, finally runtime information is straight forward. This makes it possible to dynamically lie code in a safe manner.
14.Safe:
Java does not provide any pointer like in C or C++. Hence, memory locations of a system cannot be accessed through a Java program. Therefore, any program developed in Java cannot used to hack a system.
15.Internet Ready:
Java has capability to handle TCP/IP packets. Hence, Java can use for internet application. It has several classes for internet programming, which can be used for client /server programming.
Versions or Editions of java:
JDK 1.0 This is called Java 1 platform/just Java platform(First
JDK 1.1 generation java platform)
From version JDK 1.2, JDK name has changed to J2SE that is Java 2 standard edition for development.
Java 2 standard editions (J2SE) :
JDK 1.2 i.e. J2SE 1.2 (also called Java 2.0)
JDK 1.3 i.e. J2SE 1.3 (also called Java 3.0)
JDK 1.4 i.e. J2SE 1.4 (also called Java 4.0)
JDK 5th edition i.e. J2SE 5.0 (also called Java 5.0)
JDK 6th edition i.e. J2SE 6.0 (also called Java 6.0)
JDK 7th edition i.e. J2SE 7.0 (also called Java 7.0)
JDK 8th edition i.e. J2SE 8.0 (also called Java 8.0)
JDK 9th edition i.e. J2SE 9.0 (also called Java 9.0)
JDK 10th edition i.e. J2SE 10 (also called Java 10)
JDK 11th edition i.e. J2SE 11 (also called Java 11)
JDK 12th edition i.e. J2SE 12 (also called Java 12)
JDK 13th edition i.e. J2SE 13 (also called Java 13)
JDK 14th edition i.e. J2SE 14 (also called Java 14)
JDK 15th edition i.e. J2SE 15 (also called Java 15)
JDK 16th edition i.e. J2SE 16 (also called Java 16) : Release Date, March, 16th 2021
JDK 17th edition i.e. J2SE 17 (also called Java 17) : Expected on September 2021

Note: JDK 17 means Developer version and Java 17 means Product version.

Prof. Amol M. Jagtap
M.Tech CSE
7972761065

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Prof. Amol M. Jagtap
For more contact : 7972761065