API: Application Programming Interface

API stands for application program interface. A programmer writing an application program can make a request to the Operating System using API (using graphical user interface or command interface). It is a set of routines, protocols and tools for building software and applications. It may be any type of system like a web-based system, operating-system or a database System.

 

Java Compiler: It is a predefined program that converts the high level user written code language to low level computer- understandable byte code language during the compile time

JVM(Java Virtual Machine):processes the byte code obtained from the compiler and generates an output in user-readable format.

Java API:These are integral software packages that come along with JDK.The primary intention of API is to establish communication between applications.

Example:

iostream API are used to interact with Files 

jdbc API are used to interact with DataBase

net API are used to interact with Remote Handling Files 

Advantages of API:

Example:

javadoc - Generates HTML pages of API documentation from Java source files.

 

//Program

/* API MESSAGE DISPLAY */
public class Api
{
   public static void main(String[] args)
   {
    System.out.println("This line belongs to API");
   }
}
 

ubuntu@ubuntu:~/Desktop/rkjava/api$ javac Api.java
 

ubuntu@ubuntu:~/Desktop/rkjava/api$ ls
Api.class  Api.java

 

ubuntu@ubuntu:~/Desktop/rkjava/api$ javadoc Api.java