OCP Oracle Certified Professional Java SE 11 Developer Complete Study Guide Exam 1Z0-815, Exam 1Z0-816, and Exam 1Z0-817

by Boyarsky, Jeanne; Selikoff, Scott

• ISBN13: 9781119619130
• ISBN10: 1119619130
• Edition: 1st
• Format: Paperback
• Copyright: 2020-08-11
• Publisher: Sybex

Summary

This OCP Oracle Certified Professional Java SE 11 Developer Complete Study Guide was published before Oracle announced major changes to its OCP certification program and the release of the new Developer 1Z0-819 exam. No matter the changes, rest assured this Study Guide covers everything you need to prepare for and take the exam.

NOTE: The OCP Java SE 11 Programmer I Exam 1Z0-815 and Programmer II Exam 1Z0-816 have been retired (as of October 1, 2020), and Oracle has released a new Developer Exam 1Z0-819 to replace the previous exams. The Upgrade Exam 1Z0-817 remains the same.

This is the most comprehensive prep guide available for the OCP Oracle Certified Professional Java SE 11 Developer certification—it covers Exam 1Z0-819 and the Upgrade Exam 1Z0-817 (as well as the retired Programmer I Exam 1Z0-815 and Programmer II Exam 1Z0-816)!

Java is widely-used for backend cloud applications, Software as a Service applications (SAAS), and is the principal language used to develop Android applications. This object-oriented programming language is designed to run on all platforms that support Java without the need for recompilation. Oracle Java Programmer certification is highly valued by employers throughout the technology industry.

The OCP Oracle Certified Professional Java SE 11 Developer Complete Study Guide in an indispensable resource for anyone preparing for the certification exam. This fully up-to-date guide covers 100% of exam objectives for Exam 1Z0-819 and Upgrade Exam 1Z0-817 (in addition to the previous Exam 1Z0-815 and Exam 1Z0-816). In-depth chapters present clear, comprehensive coverage of the functional-programming knowledge necessary to succeed. Each chapter clarifies complex material while reinforcing your understanding of vital exam topics. Also included is access to Sybex's superior online interactive learning environment and test bank that includes self-assessment tests, chapter tests, bonus practice exam questions, electronic flashcards, and a searchable glossary of important terms. The ultimate study aid for the challenging OCP exams, this popular guide:

• Helps you master the changes in depth, difficultly, and new module topics of the latest OCP exams
• Covers all exam objectives such as Java arrays, primitive data types, string APIs, objects and classes, operators and decision constructs, and applying encapsulation
• Allows developers to catch up on all of the newest Java material like lambda expressions, streams, concurrency, annotations, generics, and modules
• Provides practical methods for building Java applications, handling exceptions, programming through interfaces, secure coding in Java SE, and more
• Enables you to gain the information, understanding, and practice you need to pass the OCP exams

The OCP Oracle Certified Professional Java SE 11 Developer Complete Study Guide is a must-have book for certification candidates needing to pass these challenging exams, as well as junior- to senior-level developers who use Java as their primary programming language.

Author Biography

ABOUT THE AUTHORS

Jeanne Boyarsky, OCA/OCP 8 and OCP 11, is a Java Champion and has worked as a Java developer for a major bank for more than 18 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 architect for over 20 years. He is the founder of Selikoff Solutions, LLC, specializing in building custom mobile and server solutions for businesses in the tri-state New York City area.

Table of Contents

Introduction xxix

Assessment Tests lix

Part I Exam 1Z0-815, OCP Java SE 11 Programmer I 1

Chapter 1 Welcome to Java 3

Learning About the Java Environment 4

Major Components of Java 4

Downloading a JDK 5

Identifying Benefits of Java 6

Understanding the Java Class Structure 7

Fields and Methods 7

Comments 8

Classes vs. Files 10

Writing a main() Method 10

Creating a main() Method 11

Passing Parameters to a Java Program 12

Running a Program in One Line 14

Understanding Package Declarations and Imports 15

Wildcards 17

Redundant Imports 17

Naming Conflicts 18

Creating a New Package 20

Compiling and Running Code with Packages 21

Using an Alternate Directory 22

Compiling with JAR Files 24

Creating a JAR File 25

Running a Program in One Line with Packages 26

Ordering Elements in a Class 26

Code Formatting on the Exam 28

Summary 29

Exam Essentials 29

Review Questions 31

Chapter 2 Java Building Blocks 37

Creating Objects 38

Calling Constructors 38

Reading and Writing Member Fields 39

Executing Instance Initializer Blocks 40

Following Order of Initialization 41

Understanding Data Types 42

Using Primitive Types 42

Using Reference Types 46

Distinguishing between Primitives and Reference Types 47

Declaring Variables 48

Identifying Identifiers 48

Declaring Multiple Variables 51

Initializing Variables 52

Creating Local Variables 53

Passing Constructor and Method Parameters 54

Defining Instance and Class Variables 55

Introducing var 55

Managing Variable Scope 61

Limiting Scope 61

Nesting Scope 62

Tracing Scope 62

Applying Scope to Classes 63

Reviewing Scope 64

Destroying Objects 64

Understanding Garbage Collection 65

Tracing Eligibility 66

Summary 69

Exam Essentials 69

Review Questions 71

Chapter 3 Operators 81

Understanding Java Operators 82

Types of Operators 82

Operator Precedence 83

Applying Unary Operators 84

Logical Complement and Negation Operators 85

Increment and Decrement Operators 86

Working with Binary Arithmetic Operators 87

Arithmetic Operators 88

Numeric Promotion 90

Assigning Values 92

Assignment Operator 92

Casting Values 92

Compound Assignment Operators 95

Assignment Operator Return Value 96

Comparing Values 97

Equality Operators 97

Relational Operators 99

Logical Operators 101

Short-Circuit Operators 102

Making Decisions with the Ternary Operator 104

Summary 105

Exam Essentials 106

Review Questions 107

Chapter 4 Making Decisions 115

Creating Decision-Making Statements 116

Statements and Blocks 116

The if Statement 117

The else Statement 118

The switch Statement 121

Writing while Loops 128

The while Statement 128

The do/while Statement 129

Comparing while and do/while Loops 130

Infinite Loops 131

Constructing for Loops 132

The for Loop 133

The for-each Loop 138

Controlling Flow with Branching 143

Nested Loops 143

Adding Optional Labels 144

The break Statement 145

The continue Statement 147

The return Statement 149

Unreachable Code 150

Reviewing Branching 150

Summary 151

Exam Essentials 152

Review Questions 153

Chapter 5 Core Java APIs 163

Creating and Manipulating Strings 164

Concatenation 165

Immutability 166

Important String Methods 167

Method Chaining 173

Using the StringBuilder Class 174

Mutability and Chaining 175

Creating a StringBuilder 176

Important StringBuilder Methods 176

Understanding Equality 179

Comparing equals() and == 179

The String Pool 181

Understanding Java Arrays 182

Creating an Array of Primitives 183

Creating an Array with Reference Variables 185

Using an Array 187

Sorting 188

Searching 189

Comparing 190

Varargs 192

Multidimensional Arrays 192

Understanding an ArrayList 195

Creating an ArrayList 195

Using an ArrayList 197

Wrapper Classes 201

Autoboxing and Unboxing 203

Converting Between array and List 203

Using Varargs to Create a List 205

Sorting 206

Creating Sets and Maps 206

Introducing Sets 206

Introducing Maps 207

Calculating with Math APIs 208

min() and max() 208

round() 209

pow() 209

random() 210

Summary 210

Exam Essentials 211

Review Questions 212

Chapter 6 Lambdas and Functional Interfaces 223

Writing Simple Lambdas 224

Lambda Example 224

Lambda Syntax 227

Introducing Functional Interfaces 229

Predicate 230

Consumer 230

Supplier 231

Comparator 232

Working with Variables in Lambdas 233

Parameter List 233

Local Variables inside the Lambda Body 233

Variables Referenced from the Lambda Body 234

Calling APIs with Lambdas 236

removeIf() 236

sort() 237

forEach() 237

Summary 238

Exam Essentials 239

Review Questions 240

Chapter 7 Methods and Encapsulation 249

Designing Methods 250

Access Modifiers 251

Optional Specifiers 252

Return Type 253

Method Name 254

Parameter List 255

Optional Exception List 255

Method Body 256

Working with Varargs 256

Applying Access Modifiers 258

Private Access 258

Default (Package-Private) Access 259

Protected Access 261

Public Access 265

Applying the static Keyword 266

Designing static Methods and Fields 266

Accessing a static Variable or Method 267

Static vs. Instance 268

static Variables 270

Static Initialization 271

Static Imports 272

Passing Data among Methods 274

Overloading Methods 277

Varargs 279

Autoboxing 279

Reference Types 279

Primitives 281

Generics 281

Arrays 282

Putting It All Together 282

Encapsulating Data 283

Summary 285

Exam Essentials 286

Review Questions 287

Chapter 8 Class Design 297

Understanding Inheritance 298

Single vs. Multiple Inheritance 299

Inheriting Object 300

Creating Classes 301

Extending a Class 301

Applying Class Access Modifiers 303

Accessing the this Reference 304

Calling the super Reference 305

Declaring Constructors 307

Creating a Constructor 307

Default Constructor 308

Calling Overloaded Constructors with this() 310

Calling Parent Constructors with super() 312

Constructors and final Fields 316

Order of Initialization 318

Reviewing Constructor Rules 324

Inheriting Members 325

Calling Inherited Members 325

Inheriting Methods 326

Hiding Variables 338

Understanding Polymorphism 339

Object vs. Reference 341

Casting Objects 342

The instanceof Operator 343

Polymorphism and Method Overriding 344

Overriding vs. Hiding Members 346

Summary 348

Exam Essentials 349

Review Questions 351

Chapter 9 Advanced Class Design 365

Creating Abstract Classes 366

Introducing Abstract Classes 366

Defining Abstract Methods 368

Creating a Concrete Class 372

Reviewing Abstract Class Rules 374

Implementing Interfaces 375

Defining an Interface 375

Inserting Implicit Modifiers 379

Inheriting an Interface 382

Polymorphism and Interfaces 386

Reviewing Interface Rules 388

Introducing Inner Classes 390

Defining a Member Inner Class 390

Using a Member Inner Class 391

Summary 392

Exam Essentials 393

Review Questions 394

Chapter 10 Exceptions 403

Understanding Exceptions 404

The Role of Exceptions 404

Understanding Exception Types 406

Throwing an Exception 409

Recognizing Exception Classes 411

RuntimeException Classes 411

Checked Exception Classes 414

Error Classes 415

Handling Exceptions 416

Using try and catch Statements 416

Chaining catch Blocks 418

Applying a Multi-catch Block 420

Adding a finally Block 423

Finally Closing Resources 426

Throwing Additional Exceptions 432

Calling Methods That Throw Exceptions 434

Declaring and Overriding Methods with Exceptions 436

Printing an Exception 437

Summary 439

Exam Essentials 440

Review Questions 442

Chapter 11 Modules 453

Introducing Modules 454

Exploring a Module 455

Benefits of Modules 456

Creating and Running a Modular Program 458

Creating the Files 459

Compiling Our First Module 460

Running Our First Module 462

Packaging Our First Module 463

Updating Our Example for Multiple Modules 465

Updating the Feeding Module 465

Creating a Care Module 466

Creating the Talks Module 468

Creating the Staff Module 471

Diving into the module-info File 472

exports 472

requires transitive 474

provides, uses, and opens 476

Discovering Modules 477

The java Command 477

The jar Command 480

The jdeps Command 480

The jmod Command 482

Reviewing Command-Line Options 483

Summary 485

Exam Essentials 486

Review Questions 487

Part II Exam 1Z0-816, OCP Java SE 11 Programmer II Exam 1Z0-817, Upgrade OCP Java SE 11 493

Chapter 12 Java Fundamentals 495

Applying the final Modifier 496

Declaring final Local Variables 496

Adding final to Instance and static Variables 497

Writing final Methods 498

Marking Classes final 499

Working with Enums 500

Creating Simple Enums 500

Using Enums in Switch Statements 502

Adding Constructors, Fields, and Methods 503

Creating Nested Classes 506

Declaring an Inner Class 506

Creating a static Nested Class 509

Writing a Local Class 511

Defining an Anonymous Class 512

Reviewing Nested Classes 515

Understanding Interface Members 516

Relying on a default Interface Method 517

Using static Interface Methods 521

Introducing private Interface Methods 522

Introducing private static Interface Methods 523

Reviewing Interface Members 525

Introducing Functional Programming 526

Defining a Functional Interface 526

Declaring a Functional Interface with Object Methods 528

Implementing Functional Interfaces with Lambdas 530

Writing Lambda Expressions 532

Working with Lambda Variables 534

Summary 537

Exam Essentials 538

Review Questions 540

Chapter 13 Annotations 553

Introducing Annotations 554

Understanding Metadata 554

Purpose of Annotations 555

Creating Custom Annotations 558

Creating an Annotation 558

Specifying a Required Element 559

Providing an Optional Element 560

Selecting an Element Type 561

Applying Element Modifiers 561

Adding a Constant Variable 562

Reviewing Annotation Rules 562

Applying Annotations 563

Using Annotations in Declarations 563

Mixing Required and Optional Elements 565

Creating a value() Element 565

Passing an Array of Values 567

Declaring Annotation-Specific Annotations 568

Limiting Usage with @Target 568

Storing Annotations with @Retention 571

Generating Javadoc with @Documented 572

Inheriting Annotations with @Inherited 573

Supporting Duplicates with @Repeatable 573

Reviewing Annotation-Specific Annotations 575

Using Common Annotations 577

Marking Methods with @Override 577

Declaring Interfaces with @FunctionalInterface 578

Retiring Code with @Deprecated 579

Ignoring Warnings with @SuppressWarnings 580

Protecting Arguments with @SafeVarargs 582

Reviewing Common Annotations 583

Summary 585

Exam Essentials 586

Review Questions 588

Chapter 14 Generics and Collections 599

Using Method References 601

Calling Static Methods 602

Calling Instance Methods on a Particular Object 603

Calling Instance Methods on a Parameter 603

Calling Constructors 604

Reviewing Method References 604

Using Wrapper Classes 605

Using the Diamond Operator 607

Using Lists, Sets, Maps, and Queues 608

Common Collections Methods 609

Using the List Interface 613

Using the Set Interface 618

Using the Queue Interface 620

Using the Map Interface 622

Comparing Collection Types 629

Sorting Data 631

Creating a Comparable Class 631

Comparing Data with a Comparator 635

Comparing Comparable and Comparator 636

Comparing Multiple Fields 637

Sorting and Searching 639

Working with Generics 641

Generic Classes 642

Generic Interfaces 645

Raw Types 646

Generic Methods 647

Bounding Generic Types 648

Putting It All Together 653

Summary 655

Exam Essentials 657

Review Questions 658

Chapter 15 Functional Programming 669

Working with Built-in Functional Interfaces 670

Implementing Supplier 672

Implementing Consumer and BiConsumer 673

Implementing Predicate and BiPredicate 674

Implementing Function and BiFunction 675

Implementing UnaryOperator and BinaryOperator 677

Checking Functional Interfaces 678

Convenience Methods on Functional Interfaces 679

Returning an Optional 681

Creating an Optional 682

Dealing with an Empty Optional 683

Using Streams 685

Understanding the Pipeline Flow 685

Creating Stream Sources 688

Using Common Terminal Operations 691

Using Common Intermediate Operations 698

Putting Together the Pipeline 703

Working with Primitive Streams 707

Creating Primitive Streams 708

Mapping Streams 711

Using Optional with l Primitive Streams 713

Summarizing Statistics 714

Learning the Functional Interfaces for Primitives 715

Working with Advanced Stream Pipeline Concepts 718

Linking Streams to the Underlying Data 718

Chaining Optionals 718

Collecting Results 721

Summary 728

Exam Essentials 730

Review Questions 732

Chapter 16 Exceptions, Assertions, and Localization 741

Reviewing Exceptions 742

Handling Exceptions 742

Distinguishing between throw and throws 744

Examining Exception Categories 744

Inheriting Exception Classes 746

Creating Custom Exceptions 747

Declaring Exception Classes 747

Adding Custom Constructors 747

Printing Stack Traces 749

Automating Resource Management 750

Constructing Try-With-Resources Statements 750

Learning the New Effectively Final Feature 753

Understanding Suppressed Exceptions 755

Declaring Assertions 758

Validating Data with the assert Statement 758

Enabling Assertions 760

Disabling Assertions 761

Applying Assertions 761

Writing Assertions Correctly 762

Working with Dates and Times 762

Creating Dates and Times 763

Formatting Dates and Times 765

Supporting Internationalization and Localization 770

Picking a Locale 770

Localizing Numbers 773

Localizing Dates 777

Specifying a Locale Category 778

Loading Properties with Resource Bundles 779

Creating a Resource Bundle 780

Picking a Resource Bundle 782

Selecting Resource Bundle Values 783

Formatting Messages 785

Using the Properties Class 786

Summary 787

Exam Essentials 788

Review Questions 789

Chapter 17 Modular Applications 803

Reviewing Module Directives 804

Comparing Types of Modules 805

Named Modules 805

Automatic Modules 806

Unnamed Modules 809

Comparing Module Types 809

Analyzing JDK Dependencies 810

Identifying Built-in Modules 810

Using jdeps 812

Migrating an Application 815

Determining the Order 815

Exploring a Bottom-Up Migration Strategy 816

Exploring a Top-Down Migration Strategy 818

Splitting a Big Project into Modules 819

Failing to Compile with a Cyclic Dependency 820

Creating a Service 822

Declaring the Service Provider Interface 823

Creating a Service Locator 824

Invoking from a Consumer 826

Adding a Service Provider 827

Merging Service Locator and Consumer 828

Reviewing Services 831

Summary 831

Exam Essentials 832

Review Questions 833

Chapter 18 Concurrency 839

Introducing Threads 841

Distinguishing Thread Types 842

Understanding Thread Concurrency 842

Defining a Task with Runnable 843

Creating a Thread 845

Polling with Sleep 847

Creating Threads with the Concurrency API 849

Introducing the Single-Thread Executor 849

Shutting Down a Thread Executor 850

Submitting Tasks 851

Waiting for Results 852

Submitting Task Collections 856

Scheduling Tasks 857

Increasing Concurrency with Pools 860

Writing Thread-Safe Code 861

Understanding Thread-Safety 861

Protecting Data with Atomic Classes 863

Improving Access with Synchronized Blocks 865

Synchronizing on Methods 867

Understanding the Lock Framework 869

Orchestrating Tasks with a CyclicBarrier 873

Using Concurrent Collections 876

Understanding Memory Consistency Errors 877

Working with Concurrent Classes 877

Obtaining Synchronized Collections 882

Identifying Threading Problems 883

Understanding Liveness 884

Managing Race Conditions 887

Working with Parallel Streams 888

Creating Parallel Streams 889

Performing a Parallel Decomposition 890

Processing Parallel Reductions 892

Avoiding Stateful Operations 897

Summary 898

Exam Essentials 899

Review Questions 900

Chapter 19 I/O 913

Understanding Files and Directories 914

Conceptualizing the File System 914

Storing Data as Bytes 916

Introducing the File Class 916

Introducing I/O Streams 920

Understanding I/O Stream Fundamentals 920

Learning I/O Stream Nomenclature 921

Common I/O Stream Operations 927

Reading and Writing Data 927

Closing the Stream 929

Manipulating Input Streams 930

Flushing Output Streams 932

Reviewing Common I/O Stream Methods 933

Working with I/O Stream Classes 934

Reading and Writing Binary Data 934

Buffering Binary Data 935

Reading and Writing Character Data 937

Buffering Character Data 938

Serializing Data 939

Printing Data 946

Review of Stream Classes 951

Interacting with Users 952

Printing Data to the User 953

Reading Input as a Stream 954

Closing System Streams 954

Acquiring Input with Console 955

Summary 958

Exam Essentials 958

Review Questions 960

Chapter 20 NIO.2 969

Introducing NIO.2 970

Introducing Path 971

Creating Paths 972

Understanding Common NIO.2 Features 977

Interacting with Paths 980

Viewing the Path with toString(), getNameCount(), and getName() 980

Creating a New Path with subpath() 981

Accessing Path Elements with getFileName(), getParent(), and getRoot() 982

Checking Path Type with isAbsolute() and toAbsolutePath() 984

Joining Paths with resolve() 985

Deriving a Path with relativize() 985

Cleaning Up a Path with normalize() 987

Retrieving the File System Path with toRealPath() 987

Reviewing Path Methods 988

Operating on Files and Directories 989

Checking for Existence with exists() 989

Testing Uniqueness with isSameFile() 990

Making Directories with createDirectory() and createDirectories() 991

Copying Files with copy() 992

Moving or Renaming Paths with move() 994

Deleting a File with delete() and deleteIfExists() 994

Reading and Writing Data with newBufferedReader()

and newBufferedWriter() 995

Reading a File with readAllLines() 996

Reviewing Files Methods 996

Managing File Attributes 997

Discovering File Attributes 997

Improving Attribute Access 1000

Applying Functional Programming 1002

Listing Directory Contents 1002

Traversing a Directory Tree 1004

Searching a Directory with find() 1008

Reading a File with lines() 1009

Comparing Legacy java.io.File and NIO.2 Methods 1011

Summary 1012

Exam Essentials 1012

Review Questions 1014

Chapter 21 JDBC 1023

Introducing Relational Databases and SQL 1024

Identifying the Structure of a Relational Database 1026

Writing Basic SQL Statements 1027

Introducing the Interfaces of JDBC 1029

Connecting to a Database 1031

Building a JDBC URL 1031

Getting a Database Connection 1033

Working with a PreparedStatement 1036

Obtaining a PreparedStatement 1037

Executing a PreparedStatement 1037

Working with Parameters 1040

Updating Multiple Times 1043

Getting Data from a ResultSet 1045

Reading a ResultSet 1045

Getting Data for a Column 1049

Using Bind Variables 1050

Calling a CallableStatement 1051

Calling a Procedure without Parameters 1052

Passing an IN Parameter 1053

Returning an OUT Parameter 1053

Working with an INOUT Parameter 1054

Comparing Callable Statement Parameters 1054

Closing Database Resources 1055

Summary 1058

Exam Essentials 1058

Review Questions 1060

Chapter 22 Security 1069

Designing a Secure Object 1070

Limiting Accessibility 1070

Restricting Extensibility 1071

Creating Immutable Objects 1072

Cloning Objects 1075

Introducing Injection and Input Validation 1077

Preventing Injection with a PreparedStatement 1077

Invalidating Invalid Input with Validation 1080

Working with Confidential Information 1082

Guarding Sensitive Data from Output 1083

Protecting Data in Memory 1083

Limiting File Access 1084

Serializing and Deserializing Objects 1085

Specifying Which Fields to Serialize 1085

Customizing the Serialization Process 1086

Pre/Post-Serialization Processing 1087

Reviewing Serialization Methods 1090

Constructing Sensitive Objects 1091

Making Methods final 1092

Making Classes final 1092

Making the Constructor private 1093

Preventing Denial of Service Attacks 1094

Leaking Resources 1094

Reading Very Large Resources 1094

Including Potentially Large Resources 1095

Overflowing Numbers 1095

Wasting Data Structures 1096

Summary 1097

Exam Essentials 1098

Review Questions 1099

Appendix Answers to Review Questions 1105

Chapter 1: Welcome to Java 1106

Chapter 2: Java Building Blocks 1108

Chapter 3: Operators 1112

Chapter 4: Making Decisions 1115

Chapter 5: Core Java APIs 1119

Chapter 6: Lambdas and Functional Interfaces 1123

Chapter 7: Methods and Encapsulation 1125

Chapter 8: Class Design 1127

Chapter 9: Advanced Class Design 1132

Chapter 10: Exceptions 1136

Chapter 11: Modules 1140

Chapter 12: Java Fundamentals 1142

Chapter 13: Annotations 1146

Chapter 14: Generics and Collections 1149

Chapter 15: Functional Programming 1153

Chapter 16: Exceptions, Assertions, and Localization 1156

Chapter 17: Modular Applications 1160

Chapter 18: Concurrency 1162

Chapter 19: I/O 1166

Chapter 20: NIO.2 1169

Chapter 21: JDBC 1173

Chapter 22: Security 1175

Index 1177