OCP Oracle Certified Professional Java SE 11 Programmer I Study Guide

Jeanne Boyarsky, OCA/OCP 8 and OCP 11, has worked as a Java developer for a major bank for more than 17 years. She is a senior moderator at CodeRanch, and trains and mentors students of all levels, including the programming division of a FIRST robotics team.Scott Selikoff, OCA/OCP 8 and OCP 11, has been a professional Java Enterprise developer for over 20 years. He currently operates Selikoff Solutions, LLC, which provides software consulting services to businesses in the tri-state New York City area.

• Introduction xxiThe Assessment Test xliiiChapter 1 Welcome to Java 1Learning About the Java Environment 2Major Components of Java 2Downloading a JDK 3Identifying Benefits of Java 4Understanding the Java Class Structure 5Fields and Methods 5Comments 6Classes vs. Files 8Writing a main() Method 8Creating a main() Method 9Passing Parameters to a Java Program 10Running a Program in One Line 12Understanding Package Declarations and Imports 13Wildcards 15Redundant Imports 15Naming Conflicts 16Creating a New Package 18Compiling and Running Code with Packages 19Using an Alternate Directory 20Compiling with JAR Files 22Creating a JAR File 23Running a Program in One Line with Packages 24Ordering Elements in a Class 24Code Formatting on the Exam 26Summary 27Exam Essentials 27Review Questions 29Chapter 2 Java Building Blocks 35Creating Objects 36Calling Constructors 36Reading and Writing Member Fields 37Executing Instance Initializer Blocks 38Following Order of Initialization 39Understanding Data Types 40Using Primitive Types 40Using Reference Types 44Distinguishing between Primitives and Reference Types 45Declaring Variables 46Identifying Identifiers 46Declaring Multiple Variables 49Initializing Variables 50Creating Local Variables 51Passing Constructor and Method Parameters 52Defining Instance and Class Variables 53Introducing var 53Managing Variable Scope 59Limiting Scope 59Nesting Scope 60Tracing Scope 60Applying Scope to Classes 61Reviewing Scope 62Destroying Objects 62Understanding Garbage Collection 63Tracing Eligibility 64Summary 67Exam Essentials 67Review Questions 69Chapter 3 Operators 79Understanding Java Operators 80Types of Operators 80Operator Precedence 81Applying Unary Operators 82Logical Complement and Negation Operators 83Increment and Decrement Operators 84Working with Binary Arithmetic Operators 85Arithmetic Operators 86Numeric Promotion 88Assigning Values 90Assignment Operator 90Casting Values 90Compound Assignment Operators 93Assignment Operator Return Value 94Comparing Values 95Equality Operators 95Relational Operators 97Logical Operators 99Short-Circuit Operators 100Making Decisions with the Ternary Operator 102Summary 103Exam Essentials 104Review Questions 105Chapter 4 Making Decisions 113Creating Decision-Making Statements 114Statements and Blocks 114The if Statement 115The else Statement 116The switch Statement 119Writing while Loops 126The while Statement 126The do/while Statement 127Comparing while and do/while Loops 128Infinite Loops 129Constructing for Loops 130The for Loop 131The for-each Loop 136Controlling Flow with Branching 141Nested Loops 141Adding Optional Labels 142The break Statement 143The continue Statement 145The return Statement 147Unreachable Code 148Reviewing Branching 148Summary 149Exam Essentials 150Review Questions 151Chapter 5 Core Java APIs 161Creating and Manipulating Strings 162Concatenation 163Immutability 164Important String Methods 165Method Chaining 171Using the StringBuilder Class 172Mutability and Chaining 173Creating a StringBuilder 174Important StringBuilder Methods 174Understanding Equality 177Comparing equals() and == 177The String Pool 179Understanding Java Arrays 180Creating an Array of Primitives 181Creating an Array with Reference Variables 183Using an Array 185Sorting 186Searching 187Comparing 188Varargs 190Multidimensional Arrays 190Understanding an ArrayList 193Creating an ArrayList 193Using an ArrayList 195Wrapper Classes 199Autoboxing and Unboxing 201Converting Between array and List 201Using Varargs to Create a List 203Sorting 204Creating Sets and Maps 204Introducing Sets 204Introducing Maps 205Calculating with Math APIs 206min() and max() 206round() 207pow() 207random() 208Summary 208Exam Essentials 209Review Questions 210Chapter 6 Lambdas and Functional Interfaces 221Writing Simple Lambdas 222Lambda Example 222Lambda Syntax 225Introducing Functional Interfaces 227Predicate 228Consumer 228Supplier 229Comparator 230Working with Variables in Lambdas 231Parameter List 231Local Variables inside the Lambda Body 231Variables Referenced from the Lambda Body 232Calling APIs with Lambdas 234removeIf() 234sort() 235forEach() 235Summary 236Exam Essentials 237Review Questions 238Chapter 7 Methods and Encapsulation 247Designing Methods 248Access Modifiers 249Optional Specifiers 250Return Type 251Method Name 252Parameter List 253Optional Exception List 253Method Body 254Working with Varargs 254Applying Access Modifiers 256Private Access 256Default (Package-Private) Access 257Protected Access 259Public Access 263Applying the static Keyword 264Designing static Methods and Fields 264Accessing a static Variable or Method 265Static vs. Instance 266static Variables 268Static Initialization 269Static Imports 270Passing Data among Methods 272Overloading Methods 275Varargs 277Autoboxing 277Reference Types 277Primitives 279Generics 279Arrays 280Putting It All Together 280Encapsulating Data 281Summary 283Exam Essentials 284Review Questions 285Chapter 8 Class Design 295Understanding Inheritance 296Single vs. Multiple Inheritance 297Inheriting Object 298Creating Classes 299Extending a Class 299Applying Class Access Modifiers 301Accessing the this Reference 302Calling the super Reference 303Declaring Constructors 305Creating a Constructor 305Default Constructor 306Calling Overloaded Constructors with this() 308Calling Parent Constructors with super() 310Constructors and final Fields 314Order of Initialization 316Reviewing Constructor Rules 322Inheriting Members 323Calling Inherited Members 323Inheriting Methods 324Hiding Variables 336Understanding Polymorphism 337Object vs. Reference 339Casting Objects 340The instanceof Operator 341Polymorphism and Method Overriding 342Overriding vs. Hiding Members 344Summary 346Exam Essentials 347Review Questions 349Chapter 9 Advanced Class Design 363Creating Abstract Classes 364Introducing Abstract Classes 364Defining Abstract Methods 366Creating a Concrete Class 370Reviewing Abstract Class Rules 372Implementing Interfaces 373Defining an Interface 373Inserting Implicit Modifiers 377Inheriting an Interface 380Polymorphism and Interfaces 384Reviewing Interface Rules 386Introducing Inner Classes 388Defining a Member Inner Class 388Using a Member Inner Class 389Summary 390Exam Essentials 391Review Questions 392Chapter 10 Exceptions 401Understanding Exceptions 402The Role of Exceptions 402Understanding Exception Types 404Throwing an Exception 407Recognizing Exception Classes 409RuntimeException Classes 409Checked Exception Classes 412Error Classes 413Handling Exceptions 414Using try and catch Statements 414Chaining catch Blocks 416Applying a Multi-catch Block 418Adding a finally Block 421Finally Closing Resources 424Throwing Additional Exceptions 430Calling Methods That Throw Exceptions 432Declaring and Overriding Methods with Exceptions 434Printing an Exception 435Summary 437Exam Essentials 438Review Questions 440Chapter 11 Modules 451Introducing Modules 452Exploring a Module 453Benefits of Modules 454Creating and Running a Modular Program 456Creating the Files 457Compiling Our First Module 458Running Our First Module 460Packaging Our First Module 461Updating Our Example for Multiple Modules 463Updating the Feeding Module 463Creating a Care Module 464Creating the Talks Module 466Creating the Staff Module 469Diving into the module-info File 470exports 470requires transitive 472provides, uses, and opens 474Discovering Modules 475The java Command 475The jar Command 478The jdeps Command 478The jmod Command 480Reviewing Command-Line Options 481Summary 483Exam Essentials 484Review Questions 485Appendix Answers to Review Questions 491Chapter 1: Welcome to Java 492Chapter 2: Java Building Blocks 494Chapter 3: Operators 498Chapter 4: Making Decisions 501Chapter 5: Core Java APIs 505Chapter 6: Lambdas and Functional Interfaces 509Chapter 7: Methods and Encapsulation 511Chapter 8: Class Design 513Chapter 9: Advanced Class Design 518Chapter 10: Exceptions 522Chapter 11: Modules 526Index 529