API stands for Java Application Programming Interface. If you are looking for the JSP API then visit http://java.sun.com/products/servlet/2.2/javadoc/index.html and read about JSP 2.2 API.
Here is the description of important JSP API:
Classes and interfaces for the Core JSP 2.0 API.
Classes and interfaces for the JSP 2.0 Expression Language API.
Classes and interfaces for the definition of JavaServer Pages Tag Libraries.
You can Learn JSP online through our online JSP material. So, get started with JSP visit our JSP section at http://www.roseindia.net/jsp.
If you are facing any programming issue, such as compilation errors or not able to find the code you are looking for.
Ask your questions, our development team will try to give answers to your questions.