Foundations Of JAVA Language

Define Program?

  • Program is a ‘Set-of-Instructions’.

Define Programming?

  • The process of constructing program is known as Programming.

Define programmer?

  • The person who writes the programs is known as Programmer.

Note:

  • After writing the programs, we save the programs with language Extentions

Exp:

Test.c

Test.cpp

Test.java

=> The program will have the following two stages:

1.Compilation Stage

2.Execution Stage

1. Compilation Stage:

=> The process of checking the program constructed within the rules of language or not, is known as Compilation process.

Note:

=> C,C++ and Java languages will use compiler in compilation process.

=> After Compilation process is successfull

  => C and C++ programs generate Objective code

=> Java programs generate Byte Code.

2. Execution Stage:

=>The process of running the compiled code and checking the required output is generated or not,is known as Execution process.

Note:

=> Internal to execution process we have the following two SubProcesses:

(i)Loading process

=>The process of loading the required files into current running program using loader,is known as Loading process.

(ii)Linking Process

=>The process of linking the loaded files into current running program using Linker,is known as Linking process.

Note:

  • In C and c++ after loading and linking processes,the Objective code is converted into Executable code.
  • In Java lang the Byte code is executed on JVM(Java Virtual Machine) and which internally having Loader, Linker and ExecutionEngine.

Frequently Asked Question:

What is the diff b/w

(i)Objective Code

(ii)Byte Code

(i)Objective Code:

=> Objective Code is the Compiled code generated from c and c++programs.

=> While Objective generation operating System is participated, because of this reason Objective code is PlatForm dependent code.

DisAdvantage:

=>The Objective Code which is generated from one PlatForm cannot be executed on other PlatForms.

Note:

=>C and c++ languages which are generating objective codes are PlatForm dependent languages.

(ii)Byte Code:

=> Byte Code is compiled code generated from Java Programs.

=> while Byte code generation Operating System is not participated, because of this reason ByteCode is PlatForm independent code.

Advantage:

=>The ByteCode which is generated from one platform can be executed on all the platforms where JVM is available.

Note:

=>Java Lang which generates Byte Code is PlatForm independent lang.

List of Java Versions:

1995 – Java Alpha&Beta

1996 – JDK 1.0

1997 – JDK 1.1

1998 – JDK 1.2

2000 – JDK 1.3

2002 – JDK 1.4

————————–

2004 – Java5(Tiger Java)

=> JDK 1.5

=> JRE 1.5

2006 – Java6

=> JDK 1.6

=> JRE 1.6

2011 – Java7

=> JDK 1.7

=> JRE 1.7

—————————–

2014 – Java8

=> JDK 1.8

=> JRE 1.8

2017 – Java9

=> JDK 1.9

=> JRE 1.9

2018,2019,2020

=> Java10,Java11,Java12,Java13,Java14

———————————————–

Frequently Asked Questions:

What is the diff b/w

(i)JDK

(ii)JRE

(i)JDK:

=>JDK stands for ‘Java Development Kit’ and which provides JavaCompiler, JavaLib and JVM.

JavaCompiler – which is used for compilation process.

JavaLib – which provides the Built-In classes and Interfaces used in Construction.

=>we use word ‘java’ to represent JavaLib.

=>JavaLib is collection of ‘packages’.

=>packages are collection of Classes and Interfaces.

=>Classes and Interfaces are the collection of Variables and Methods.

List of some important packages from JavaLib:

Core Java Packages:

java.lang – Language package(default package)

java.util – Utility package

java.io – IO Streams and Files package

java.net – Networking package

Adv Java Packages:

java.sql – DB Connection package

javax.servlet – Servlet programming package

javax.servlet.jsp – JSP Programming package

JVM – JVM is used to execute Byte code.

(ii)JRE:

=>JRE Stands for ‘Java Runtime Environment’ and which provides

only ‘JavaLib and JVM’. (JRE will not provide Java Compiler)

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