Application programmaing Interface (API)
Java API is not but a set of classes and interfaces that comes with the
JDK. Java API is actually a huge collection of library routines that
performs basic programming tasks such as looping, displaying GUI form
etc. In the Java API classes and interfaces are packaged in packages.
All these classes are written in Java programming language and runs on
the JVM. Java classes are platform independent but JVM is not platform
independent. You will find different downloads for each OS.
Java Collections API - Presentation: