Notes

Arrays
-a collection is a group of generic objects
Streams
-uses buffers, system.out sends to buffer then to screen
-System.in/System.out are predefined
-System.in.read() returns a byte (8 bits) of data
-System.in.read() returns -1 when it has nothing left
-format string, which defines the format of the text that will be printed along with any number of placeholders for printing numeric values. These placeholders are known as format specifiers. Format specifiers define the type of values being printed in place of the format specifier.
-%(flags)(width)(.precision)specifier
Inheritance
-The term derived class (or subclass) refers to a class that is derived from another class that is known as a base class (or superclass). Any class may serve as a base class; no changes to the declaration of that class are required.
-can call protected but not private
-Protected only allows access by members of derived classes and other classes in the same package.
-Polymorphism refers to determining which program behavior to execute depending on data types. Method overloading is a form of compile-time polymorphism wherein the compiler determines which of several identically-named methods to call based on the method's arguments. Another form is runtime polymorphism wherein the compiler cannot make the determination but instead the determination is made while the program is running.
-an abstract method lacks an implementation. A class that has at least one abstract method requires an additional abstract modifier prepended to its class definition and is known as an abstract base class, meaning objects cannot be defined of that type.
-An item of type ProduceItem may be added to an ArrayList of type ArrayList<GenericItem>.
ProduceItem is derived from GenericItem. Thus, a ProduceItem object can be implicitly casted to GenericItem and added to such an ArrayList.
-The Object class is the base class for all classes. Thus, an item of any class type is implicitly casted to the Object type and added to the ArrayList.