OCP II

1 Introduction

• Course Objectives 
• Introductions 
• Audience 
• Prerequisites
• Course Roadmap
• Lesson Format
• Practice Environment
• How Do You Learn More After the Course? 
• Additional Resources 

2 Java OOP Review

• Objectives 
• Java Language Review 
• A Simple Java Class: Employee 
• Encapsulation: Private Data, Public Methods 
• Subclassing 
• Constructors in Subclasses 
• Using super 
• Using Access Control 
• Protected Access Control: Example 
• Inheritance: Accessibility of Overriding Methods 
• Final Methods 
• Final Classes
• Applying Polymorphism 
• Overriding methods of Object Class 
• Overriding methods of Object Class: toString Method 
• Overriding methods of Object Class: equals Method 
• Overriding methods of Object Class: hashCode Method 
• Casting Object References 
• Upward Casting Rules 
• Downward Casting Rules 
• Methods Using Variable Arguments 
• Static Imports 
• Nested Classes 
• Example: Member Class 
• What Are Enums? 
• Complex Enums 
• Methods in Enums 
• Summary 
   

3 Exception Handling and Assertions

• Objectives 
• Error Handling 
• Exception Types 
• Exception Handling Techniques in Java 
• Exception Handling Techniques: try Block 
• Exception Handling Techniques: finally Clause 
• Exception Handling Techniques: try-with-resources 
• Exception Handling Techniques: try-with-resources Improvements 
• Exception Handling Techniques: | operator in a catch block 
• Exception Handling Techniques: Declaring Exceptions 
• Creating Custom Exceptions 
• Assertions 
• Assertion Syntax 
• Internal Invariants 
• Control Flow Invariants 
• Class Invariants 
• Controlling Runtime Evaluation of Assertions 
   

4 Java Interfaces

• Objectives 
• Java Interfaces 
• Java SE 7 Interfaces 
• Implementing Java SE 7 Interface Methods 
• Example: Implementing abstract Methods 
• Example: Duplicating Logic 
• Implementing Methods in Interfaces 
• Example: Implementing default Methods 
• Example: Inheriting default Methods 
• Example: Overriding a default Method 
• What About the Problems of Multiple Inheritance?
• Inheritance Rules of default Methods 
• Interfaces Don't Replace Abstract Classes 
• What If default Methods Duplicate Logic? 
• Duplication Between default Methods 
• The Problem with This Approach 
• Introducing private Methods in Interfaces 
• Example: Using private Methods to Reduce Duplication Between
• default Methods 
• Types of Methods in Java SE 9 Interfaces 
• Anonymous Inner Classes 
• Anonymous Inner Class: Example 
   

5 Collections and Generics

• Objectives 
• Type-Wrapper Classes 
• Autoboxing and Auto-Unboxing 
• Generic Methods 
• A Generic Method 
• Generic Classes 
• Generic Cache Class 
• Testing the Generic Cache Class 
• Generics with Type Inference Diamond Notation 
• Java SE 9: Diamond Notation with Anonymous Inner Classes 
• Collections 
• Collections Framework in Java 
• Benefits of the Collections Framework 
• Collection Types 
• Key Collections Interfaces 
• ArrayList 
• ArrayList Without Generics
• Generic ArrayList 
• TreeSet: Implementation of Set 
• Map Interface 
• TreeMap: Implementation of Map 
• Stack with Deque: Example 
• Ordering Collections 
• Comparable: Example 
• Comparable Test: Example 
• Comparator Interface 
• Comparator: Example 
• Comparator Test: Example 
• Wildcards 
• Wildcards: Upper Bound 
• Why Use Generics? 
• Java SE 9: Convenience Methods for Collections 
• of Convenience Method 
• Overloading of Method 
• ofEntries Method for Maps 
• Features of Convenience Methods 
   

6 Functional Interfaces and Lambda Expressions

• Objectives 
• Problem Statement 
• RoboCall Class
• RoboCall Every Person 
• RoboCall Use Case: Eligible Drivers 
• RoboCall Use Case: Eligible Voters 
• RoboCall Use Case: Legal Drinking Age 
• Solution: Parameterization of Values 
• Solution: Parameterized Methods 
• Parameters for Age Range 
• Using Parameters for Age Range 
• Corrected Use Case 
• Parameterized Computation 
• How To Pass a Function in Java? 
• Prior to Java SE 8: Pass a Function Wrapped in an Object
• Prior to SE 8: Abstract Behavior With an Interface 
• Prior to SE 8: Replace Implementation Class with Anonymous Inner Class 
• Lambda Solution: Replace Anonymous Inner Class with Lambda Expression 
• Rewriting the Use Cases Using Lambda 
• What Is a Lambda? 
• What is a Functional Interface 
• Which of These Interfaces Are Functional Interfaces? 
• Lambda Expression 
• Using Lambdas
• Which of The Following Are Valid Lambda Expressions? 
• Lambda Expression: Type Inference 
• To Create a Lambda Expression 
• Examples of Lambdas
• Statement Lambdas: Lambda with Body
• Examples: Lambda Expression 
• Lambda Parameters 
• Local-Variable Syntax for Lambda Parameters
• Functional Interfaces: Predicate 
• Using Functional Interfaces 

7 Collections, Streams, and Filters

• Objectives 
• Collections, Streams, and Filters 
• The RoboCall App 
• Collection Iteration and Lambdas 
• RoboCallTest07: Stream and Filter 
• Stream and Filter 
• RobocallTest08: Stream and Filter Again 
• SalesTxn Class 
• Java Streams 
• The Filter Method 
• Filter and SalesTxn Method Call 
• Method References 
• Method Chaining 
• Pipeline Defined 

8 Lambda Built-in Functional Interfaces

• Objectives 
• Built-in Functional Interfaces 
• The java.util.function Package 
• Example Assumptions 
• Predicate 
• Predicate: Example 
• Consumer 
• Consumer: Example 
• Function 
• Function: Example 
• Supplier 
• Supplier: Example 
• Primitive Interface 
• Return a Primitive Type 
• Return a Primitive Type: Example 
• Process a Primitive Type 
• Process Primitive Type: Example 
• Binary Types 
• Binary Type: Example 
• Unary Operator 
• UnaryOperator: Example 
• Wildcard Generics Review 
• A Closer Look at Consumer
• Interface List<E> use of forEach method 
• Example of Range of Valid Parameters 
• Plant Class Example 
• TropicalFruit Class Example 
• Use of Generic Expressions and Wildcards 
• Consumer andThen method 
• Using Consumer.andThen method 
   

9 Lambda Operations

• Objectives 
• Streams API 
• Types of Operations 
• Extracting Data with Map 
• Taking a Peek 
• Search Methods: Overview 
• Search Methods 
• Optional Class 
• Short-Circuiting Example 
• Stream Data Methods 
• Performing Calculations 
• Sorting 
• Comparator Updates 
• Saving Data from a Stream 
• Collectors Class 
• Quick Streams with Stream.of
• Flatten Data with flatMap 
• flatMap in Action 

10 The Module System

• Objectives 
• Module System 
• Module System: Advantages 
• Java Modular Applications 
• What Is a Module? 
• A Modular Java Application 
• Issues with Access Across Nonmodular JARs 
• Dependencies Across Modules 
• What Is a Module? 
• Module Dependencies with requires 
• Module Package Availability with exports 
• Module Graph 1 
• Module Graph 2 
• Transitive Dependencies 
• Access to Types via Reflection 
• Example Hello World Modular Application Code 
• Example Hello World Modular File Structure 
• Compiling a Modular Application
• Single Module Compilation Example 
• Multi Module Compilation Example 
• Creating a Modular JAR 
• Running a Modular Application
• The Modular JDK 
• Java SE Modules
• The Base Module
• Finding the Right Platform Module
• Illegal Access to JDK Internals in JDK 9
• What Is a Custom Runtime Image?
• Link Time 
• Using jlink to Create a Runtime Image 
• Example: Using jlink to Create a Runtime Image 
• Examining the Generated Image 
• Modules Resolved in a Custom Runtime Image 
• Advantages of a Custom Runtime Image 
• JIMAGE Format 
• Running the Application 
   

11 Migrating to a Modular Application

• Objectives 
• Topics 
• The League Application 
• Run the Application
• The Unnamed Module 
• Topics 
• Top-down Migration and Automatic Modules 
• Automatic Module 
• Top-Down Migration 
• Creating module-info.java—Determining Dependencies
• Check Dependencies 
• Library JAR to Automatic Module 
• Typical Application Modularized 
• Topics 
• Bottom-up Migration 
• Bottom-Up Migration 
• Modularized Library 
• Run Bottom-Up Migrated Application 
• Fully Modularized Application 
• Module Resolution 
• Topics 
• More About Libraries 
• Run Application with Jackson Libraries 
• Open Soccer to Reflection from Jackson Libraries 
• Topics 
• Split Packages 
• Splitting a Java 8 Application into Modules 
• Java SE 8 Application Poorly Designed with Split Packages 
• Migration of Split Package JARs to Java SE 9 
• Addressing Split Packages
• Topics 
• Cyclic Dependencies 
• Addressing Cyclic Dependency 1 
• Addressing Cyclic Dependency 2 
• Top-down or Bottom-up Migration Summary 

• Objectives
• Topics 
• Modules and Services 
• Components of a Service 
• Produce and Consume Services 
• Module Dependencies Without Services 
• Service Relationships 
• Expressing Service Relationships 
• Topics 
• Using the Service Type in competition 
• Choosing a Provider Class 
• Module Dependencies and Services 1 
• Module Dependencies and Services 2
• Module Dependencies and Services 3 
• Designing a Service Type 
• Topics 
• TeamGameManager Application with Additional Services 
• module-info.java for competition module 
• module-info.java for league and knockout modules 
• module-info.java for soccer and basketball modules 

13 Concurrency

• Objectives 
• Task Scheduling 
• Legacy Thread and Runnable 
• Extending Thread 
• Implementing Runnable 
• The java.util.concurrent Package 
• Recommended Threading Classes 
• java.util.concurrent.ExecutorService 
• Example ExecutorService 
• Shutting Down an ExecutorService 
• java.util.concurrent.Callable 
• Example Callable Task 
• java.util.concurrent.Future 
• Example 
• Threading Concerns 
• Shared Data 
• Problems with Shared Data 
• Nonshared Data 
• Atomic Operations 
• Out-of-Order Execution 
• The synchronized Keyword 
• synchronized Methods 
• synchronized Blocks 
• Object Monitor Locking 
• Threading Performance 
• Performance Issue: Examples 
• java.util.concurrent Classes and Packages 
• The java.util.concurrent.atomic Package 
• java.util.concurrent.CyclicBarrier 
• Thread-Safe Collections 
• CopyOnWriteArrayList: Example 

14 Parallel Streams

• Objectives
• Streams Review 
• Old Style Collection Processing 
• New Style Collection Processing 
• Stream Pipeline: Another Look 
• Styles Compared 
• Parallel Stream 
• Using Parallel Streams: Collection 
• Using Parallel Streams: From a Stream 
• Pipelines Fine Print
• Embrace Statelessness 
• Avoid Statefulness 
• Streams Are Deterministic for Most Part 
• Some Are Not Deterministic 
• Reduction 
• Reduction Fine Print 
• Reduction: Example
• A Look Under the Hood 
• Illustrating Parallel Execution 
• Performance
• A Simple Performance Model 

15 Terminal Operations: Collectors

• Objectives 
• Agenda 
• Streams and Collectors Versus Imperative Code 
• Predefined Collectors 
• A Simple Collector 
• A More Complex Collector
• Agenda 
• The Three Argument collect Method of Stream 
• The collect Method Used with a Sequential Stream 
• The collect Method Used with a Parallel Stream 
• The collect Method: Collect to an ArrayList Example 
• Agenda 
• The Single Argument collect Method of Stream 
• Using Predefined Collectors From the Collectors Class 
• List of Predefined Collectors 
• Stand-Alone Collectors 
• Stand-Alone Collector:List all Elements 
• maxBy() Example 
• Adapting Collector: filtering() 
• Composing Collectors : groupingBy() 
• Composing Collectors: Using Mapping 
• toMap() and Duplicate Keys 
• Agenda
• groupingBy and partitioningBy Collectors 
• Stand-Alone groupingBy: Person Elements By City 
• Stream Operations Or Equivalent Collectors? 
• Stream Operations Or Equivalent Collectors with groupingBy 
• Stream.count(), Collectors.counting and groupingBy 
• Composing Collectors: Tallest in Each City 
• groupingBy: Additional Processing with entrySet() 
• Agenda
• Nested Values 
• Data Organization of ComplexSalesTxn 
• Displaying Nested Values: Listing Line Items in Each Transaction 
• Displaying Nested Values: Listing Line items 
• Displaying Nested Values: Grouping LineItem elements 
• groupingBy Examples for ComplexSalesTxn 
• Group Items by Salesperson 
• Agenda 
• Complex Custom Collectors 
• The collect Method: Using a Custom Collector 
• Creating a Custom Collector: Methods to Implement 
• Custom Example MyCustomCollector 
• Finisher Example MyCustomCollector
• A More Complex Collector 
• A More Complex Collector CustomGroupingBy 

16 Creating Custom Streams

• Objectives 
• Topics 
• Performance: Intuition and Measurement 
• Parallel Versus Sequential Example 
• Spliterator 
• Decomposition with trySplit() 
• Integration with Streams
• Modifying LongStream Spliterator 
• Spliterator TestSpliterator 
• Using TestSpliterator 
• Topics
• Creating a Custom Spliterator 
• Is a Custom Spliterator Needed for a Game Engine? 
• A Tic-Tac-Toe Engine Using the map Method of Stream 
• A Custom Spliterator Example for a Custom Collection 
• Custom N-ary Tree 
• Possible Implementation for NaryTreeSpliterator 
• Stream<Node> in Use 
• Implementing Parallel Processing 
• Stream<Node> in Use 
• Summary of NTreeAsListSpliterator 

17 Java I/O Fundamentals and File I/O (NIO.2)

• Objectives 
• Java I/O Basics 
• I/O Streams 
• I/O Application 
• Data Within Streams 
• Byte Stream InputStream Methods 
• Byte Stream: Example 
• Character Stream Methods 
• Character Stream: Example 
• I/O Stream Chaining 
• Chained Streams: Example 
• Console I/O 
• Writing to Standard Output 
• Reading from Standard Input 
• Channel I/O 
• Persistence 
• Serialization and Object Graphs 
• Transient Fields and Objects 
• Transient: Example 
• Serial Version UID 
• Serialization: Example 
• Writing and Reading an Object Stream 
• Serialization Methods 
• readObject: Example 
• New File I/O API (NIO.2) 
• Limitations of java.io.File 
• File Systems, Paths, Files 
• Relative Path Versus Absolute Path 
• Java NIO.2 Concepts 
• Path Interface 
• Path Interface Features 
• Path: Example 
• Removing Redundancies from a Path 
• Creating a Subpath 
• Joining Two Paths 
• Symbolic Links 
• Working with Links 
• File Operations
• BufferedReader File Stream 
• NIO File Stream 
• Read File into ArrayList 
• Managing Metadata 

18 Secure Coding Guidelines

• Objectives 
• Java SE Security Overview 
• Secure Coding Guidelines 
• Vulnerabilities 
• Secure Coding Antipatterns 
• Antipatterns in Java 
• Fundamentals 
• Fundamentals: Why Should I Care? 
• Denial of Service 
• Confidential Information 
• Injection and Inclusion 
• Accessibility and Extensibility 
• Input Validation 
• Mutability 
• Object Construction 
• Serialization and Deserialization 

19 Building Database Applications with JDBC

• Objectives 
• What Is the JDBC API? 
• What Is JDBC Driver? 
• Connecting to a Database 
• Obtaining a JDBC Driver 
• Register the JDBC driver with the DriverManager 
• Constructing a Connection URL 
• Establishing a Connection 
• Using the JDBC API 
• Key JDBC API Components 
• Writing Queries and Getting Results 
• Using a ResultSet Object 
• CRUD Operations Using JDBC API: Retrieve 
• CRUD Operations Using JDBC: Retrieve 
• CRUD Operations Using JDBC API: Create 
• CRUD Operations Using JDBC API: Update 
• CRUD Operations Using JDBC API: Delete 
• SQLException Class 
• Closing JDBC Objects 
• try-with-resources Construct 
• Using PreparedStatement 
• Using PreparedStatement: Setting Parameters 
• Executing PreparedStatement 
• PreparedStatement:Using a Loop to Set Values 
• Using CallableStatement 

20 Localization

• Objectives 
• Why Localize? 
• A Sample Application 
• Locale 
• Properties 
• Loading and Using a Properties File 
• Loading Properties from the Command Line 
• Resource Bundle 
• Resource Bundle File 
• Sample Resource Bundle Files 
• Initializing the Sample Application 
• Sample Application: Main Loop
• The printMenu Method 
• Changing the Locale
• Sample Interface with French 
• Format Date and Currency 
• Displaying Currency 
• Formatting Currency with NumberFormat 
• Displaying Dates 2
• Displaying Dates with DateTimeFormatter 
• Format Styles