Java APIs include two big groups of APIs and libraries that implement them:
- Java core packages (http://www.oracle.com/technetwork/java/api-141528.html) that come with the Java installation and are included in the JDK
- Other frameworks and libraries that can be downloaded separately, such as Apache Commons APIs (https://commons.apache.org), for example, or the three libraries we have already included as dependencies in the Maven pom.xml file of our demo project. The vast majority of them can be found in the Maven repository (https://mvnrepository.com), but a variety of new and experimental libraries and frameworks can be found eslewhere.