Core Java API
API ( Application program interface) is a library for pre-written packages , interfaces , classes , methods. When Java we originally released , it included a set of eight packages called the core Java API. Today , the Java API contains large number of packages. A package is a collection of classes , methods and respective objects. Collection packages is referred as API.
Java API has three stages
- First stage shows classes and packages. When a particular package is selected then the ,
- Second stage will shows respective classes, interfaces and exceptions of that particular package.
- The third stage helps the programmers to use that methods , objects by implementing or extending the respective package.
Let’s take an example , while developing a real time application. We may require some functions in our program ,which makes us complex to write those functions or code in our program it’s a time taking process and also the program looks very long to understand. So in this case we use those functions by importing from the Java API which is already defined. This makes the developers very easy to develop their application. ‘java.lang‘ package is the core package for developing the core Java applications , it provides core classes , methods and objects.
you can also create your own package by wrapping all your developed classes into one package and name that package by your own name. You can use that package which you developed ,whenever you get to use it this can be well explained in packages chapter. Here you can view the full Java packages which includes core Java API and advance Java API as well as tools API , where we can use while developing our applications.
To view the list of packages available in Java , please visit our Java packages page.