And on this model, what is Java?

Java is classes -- a huge set of standardized classes, so for most things you want to do, you choose one of those standard classes instead of deciding "which one of the hundred libraries made for this purpose should I use in this project?".

At least this was until the set of standardized classes became so huge that it often contains two or three different ways to do the same thing, and for web development external libraries are used anyway. (So we have AWT, Swing and JavaFX; java.io and java.nio; but we are still waiting for the lambda functions.)