Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs. Abstract classes ...

Nested classes are classes that are declared as members of other classes or scopes. Nesting classes is one way to better organize your code. For example, say you have a non-nested class (also ...

Interfaces, however, support multiple inheritances where abstract classes don't. Implementation is done similarly in Java. For example, using the keyword implements will make a Java interface, while ...

To enable unit-testing class ComponentAImpl, the implementation of interface ComponentB must be injected into ComponentAImpl. The Java code below shows the details of how to use a variant of Abstract ...