JAVA TECHNOLOGY

Java is a high level programming language which is used for creating various types of software's or applications. Types of java applications:- 1)     Stand alone application 2)     Desktop based application          3)     Web based application 4)     Enterprise application etc. Stand alone application:- Stand alone application run on single machine without user interface and every stand alone application having main method. Desktop based application:- Desktop based application also run on single machine with user interface and every Desktop based application having main method. Web based application:- Web based application run on web, web based application not required main method but for such types of application need server. Enterprise application:- Enterprise application is category of web application where doing some business o...

Object:- Object is real time entity exist in the real world , the basic purpose of object is to transfer data from one location to another location.object is small memory , allocated inside primary memory(RAM).in java object created inside heap memory,actually in java RAM memory  is divided into some segment according to the type of variables for example. RAM==>Heap area+Stack area+String constant pool+class area  etc. when object created then inside object only non static class variables occupied memory and initialize with default values. non static class variables also known as instance variable reside into object in heap area,static variables occupied memory in class area at the time of class loading from HARD disk to RAM and all local variables occupied memory in stack area when reaching to variables. object  created from the class then what object contains is depend on class structure or class members.             ...

Abstraction  is a one of the great feature of Oops,in this feature hide entire details of product, show only requirement specifications(what product will do). The main purpose behind abstraction is to increase productivity or use of product without knowledge of product implementation. in this case the person don't know how product  was implemented but know how product works or action of product. In java abstraction is achieved by abstract class and interface,here interface provide 100% abstraction and abstract class provide partial abstraction. For example: - ATM machine is example of abstraction.  every technical and non-technical person use facility of ATM without knowing the entire process. they know if they click on withdraw button then they can withdraw money from ATM machine but they don't know when they click on withdraw button the request is send to the server and after go into database and so on. Here ATM machine show only requirement specificat...

Some small concept about OOPs:- In many books and website write about OOPs concepts as hundred percent object oriented, pure object oriented and partial object oriented language. Hundred percent object oriented:- In the hundred percent object oriented movie hero is object, without object program is incomplete that means can not execute program without object. Without class and object programming or application development is not possible. Example of hundred percent object oriented language is  Smalltalk . Pure object oriented:- In the object oriented cinema obviously object is the hero. In pure object oriented language object having same importance but in this having some relax that is without creating object we can successfully execute our application. So in the object oriented programming without class we cannot create or run our application, class is must. Example of pure object oriented language is  Java . Partial object oriented:- In this type of la...

Minimum requirement Minimum requirement:- Very first you have to install jdk software in your machine, automatically JRE will be install in your machine. In jdk folder you got a another folder name is bin (binary) folder that contains all tools or .exe files like javac,java,appletviewer,……are used for test a application or for execution of program. In the above installation process all folders comes into one main folder name is java,so java folder contains two folder one is jdk and another is Jre. Jre folder contains all the required library files in the form of .jar (java archieve file) files. Requirement on developer machine:- JDK+JRE. Requirement on client machine:- JRE. Jdk  is used for developed an application. Jre  is used for use (run) an application. For running a java application we must set path variable, path is environment variable which is used by operating system. Path variable can contains more than one value. We can set path ...

Syntax of main method in java is    public static void main(String[]args)  before understanding about main method we have to understand that who is responsible for main method.if we write a simple program or write a simple java class without main method like      Test.java           class Test      {      } above program will compile successfully.for compilation of  java file use  javac tool  or  javac.exe  file. javac Test.java it means compiler checks only syntax of class that means compiler does not check the main method in the file or program,so that compiler is not responsible for main method in java. After successfully compilation of above program we have to run the generated byte code. java Test Error: Main method not found in class Test, please define the main method as:    public static void main(String[] args) So JVM...