- Program is a ‘Set-of-Instructions’.
- The process of constructing program is known as Programming.
- The person who writes the programs is known as Programmer.
- After writing the programs, we save the programs with language Extentions
=> The program will have the following two stages:
1. Compilation Stage:
=> The process of checking the program constructed within the rules of language or not, is known as Compilation process.
=> 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.
=> Internal to execution process we have the following two SubProcesses:
=>The process of loading the required files into current running program using loader,is known as Loading process.
=>The process of linking the loaded files into current running program using Linker,is known as Linking process.
- 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
=> 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.
=>The Objective Code which is generated from one PlatForm cannot be executed on other PlatForms.
=>C and c++ languages which are generating objective codes are PlatForm dependent languages.
=> 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.
=>The ByteCode which is generated from one platform can be executed on all the platforms where JVM is available.
=>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
Frequently Asked Questions:
What is the diff b/w
=>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.
=>JRE Stands for ‘Java Runtime Environment’ and which provides
only ‘JavaLib and JVM’. (JRE will not provide Java Compiler)