What are the differences and connections between Java API and Android API?

Api is just a general term, which provides a series of interfaces for developers to use. Developers don't need to figure out the implementation method, which saves development time. No matter what Api, their functions are the same. As for the underlying implementation of Api, it is different. Since Anroid is also written in a part of the java language, most of the Android API you mentioned should also be java content. There are many similarities between the two. But many new APIs are not available in java. Because Android is aimed at mobile devices, a lot of content is not available in java.