Java RefresherFeatures and Benefits of Java (OCA Objective 1.5)Identifiers and Keywords (OCA Objectives 1.2 and 2.1)Legal IdentifiersOracle’s Java Code ConventionsDefine Classes (OCA Objectives 1.2, 1.3, 1.4, 6.4, and 7.5)Source File Declaration RulesUsing the javac and java CommandsUsing public static void main(String[ ] args)Import Statements and the Java APIStatic Import StatementsClass Declarations and ModifiersExercise 1-1: Creating an Abstract Superclass and Concrete SubclassUse Interfaces (OCA Objective 7.5)Declaring an InterfaceDeclaring Interface ConstantsDeclaring default Interface MethodsDeclaring static Interface MethodsDeclare Class Members (OCA Objectives 2.1, 2.2, 2.3, 4.1, 4.2, 6.2, 6.3, and 6.4)Access ModifiersNonaccess Member ModifiersConstructor DeclarationsVariable DeclarationsDeclare and Use enums (OCA Objective 1.2)Declaring enumsCertification SummaryTwo-Minute DrillQ&A Self TestSelf Test Answers