Adapter pattern works as a bridge between two incompatible/unrelated interfaces/classes.

In real life, the card reader is the example. The corresponding diagram looks like next:

The read of CardReader will call function of MemoryCard to read its data.

From the above diagram, the CardReader is adapter, MemoryCard named adaptee and the Slot called the target.

Adapter pattern contains object adapter and class adapter. Above diagram shows the object adapter, it use composition.

If CardReader implements Slot and extends MemoryCard, this is class adapter.

Arrays.asList is an example of adapter pattern.