What is an object oriented program?

Answer 1

The term "object-oriented program" is essentially meaningless. Object-oriented programming applies to high-level source code, not to programs.

High-level source code does not create a program as such because because the high-level instructions are far too abstract for the machine to understand. In order to create an actual program, the high-level symbolic code must be converted to native machine code, the only language the machine actually understands. This is achieved through compilation or interpretation or a combination of the two. Machine code is an entirely procedural language; there is no such thing as object-oriented machine code.

Machine code is non-portable. To overcome this, a compiler may convert the source code to an intermediate form such as byte code. Byte code is usually portable but it still needs to be converted to native machine in order to execute. This is achieved by an interpreter. The interpreter handles the execution, converting byte code to machine code while the byte code is executing within the interpreter. Although portable, byte code has to be interpreted every time it is executed, so it is much slower to execute than native machine code. However, like machine code, byte code is entirely procedural.

Although it is (theoretically) possible to execute high-level object-oriented instructions through interpretation, it makes no sense to do so as this would only reduce performance even further. The whole point of compiling to byte code is to produce code that can be efficiently interpreted in order to keep performance as high as possible.

Answer 2

//This is a simple object oriented program that prints "Hello World!"

public class Main {

// This method is the method that is executed first in the program.

public static voidmain(String[] args) {

//create an instance of class Greeter

new Greeter();

}

}

Public class Greeter{

// This method is executed when a new instance of Greeter is created

public Greeter(){

//print "Hello World!"

System.out.println("Hello World!")

}

}