OCP Oracle Certified Professional Java SE 11 Programmer I Study Guide - Exam 1Z0-815

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