So far, this series has covered class declaration ... Listing 4. Counter.java // Counter.java interface Counter { void increment (); int getCount (); } The Counter interface introduces a counter ...

Notice the detail that interface methods are implicitly abstract. This means we don’t need to explicitly declare them as abstract. When default methods were introduced in Java 8, some developers ...

An interface is implicitly abstract. You do not need to use the abstract keyword when declaring an interface. Each method in an interface is also implicitly abstract, so the abstract keyword is not ...

The implementation of Java 8 Lambda expressions required an introduction to a number of new interfaces with ... all classes that implement the UnaryOperator interface. We will use generics in the ...