OCAJP/OCPJP Resources

Review exam topics/syllabus for OCP Java 21 1Z0-830 Certification Exam (As of 2024/07/07)

Handling Date, Time, Text, Numeric and Boolean Values        

• Use primitives and wrapper classes. Evaluate arithmetic and boolean expressions, using the Math API and by applying precedence rules, type conversions, and casting.
• Manipulate text, including text blocks, using String and StringBuilder classes.
• Manipulate date, time, duration, period, instant and time-zone objects including daylight saving time using Date-Time API.

Controlling Program Flow        

• Create program flow control constructs including if/else, switch statements and expressions, loops, and break and continue statements.

Using Object-Oriented Concepts in Java        

• Declare and instantiate Java objects including nested class objects, and explain the object life-cycle including creation, reassigning references, and garbage collection.
• Create classes and records, and define and use instance and static fields and methods, constructors, and instance and static initializers.
• Implement overloaded methods, including var-arg methods.
• Understand variable scopes, apply encapsulation, and create immutable objects. Use local variable type inference.
• Implement inheritance, including abstract and sealed types as well as record classes. Override methods, including that of the Object class. Implement polymorphism and differentiate between object type and reference type. Perform reference type casting, identify object types using the instanceof operator, and pattern matching with the instanceof operator and the switch construct.
• Create and use interfaces, identify functional interfaces, and utilize private, static, and default interface methods.
• Create and use enum types with fields, methods, and constructors.

Handling Exceptions        

• Handle exceptions using try/catch/finally, try-with-resources, and multi-catch blocks, including custom exceptions.

Working with Arrays and Collections        

• Create arrays, List, Set, Map and Deque collections, and add, remove, update, retrieve and sort their elements.

Working with Streams and Lambda expressions        

• Use Java object and primitive Streams, including lambda expressions implementing functional interfaces, to create, filter, transform, process, and sort data.
• Perform decomposition, concatenation, and reduction, and grouping and partitioning on sequential and parallel streams.

Packaging and Deploying Java Code         

• Define modules and expose module content, including that by reflection, and declare module dependencies, define services, providers, and consumers.
• Compile Java code, create modular and non-modular jars, runtime images, and implement migration to modules using unnamed and automatic modules.

Managing Concurrent Code Execution        

• Create both platform and virtual threads. Use both Runnable and Callable objects, manage the thread lifecycle, and use different Executor services and concurrent API to run tasks.
• Develop thread-safe code, using locking mechanisms and concurrent API.
• Process Java collections concurrently and utilize parallel streams.

Using Java I/O API        

• Read and write console and file data using I/O streams.
• Serialize and de-serialize Java objects.
• Construct, traverse, create, read, and write Path objects and their properties using the java.nio.file API.

Implementing Localization        

• Implement localization using locales and resource bundles. Parse and format messages, dates, times, and numbers, including currency and percentage values.

1. New to programming: 1+ Year 
2. An expert in another language such as Python or JavaScript: 6+ months 
3. Experienced in Java and have been programming in Java professionally for about an year: 3+ months 
4. Already OCA 8 certified recently: 3+ months
5. Already OCP 8 or OCP 11 certified recently: 1+ months 

1. The book is huge at 1800 pages and comes in two volumes. I can easily see why that is. First, the exam covers a wide range of topics ranging from beginner to expert level. Any book that claims to prepare a student for this exam will be thick. Second, this book doesn't cut corners. If the authors feel something is important enough to be told and explained, then it is covered even if it is not directly mentioned in the exam. Third, the book can be used even by a Java beginner, so concepts are taught from the ground up.
   
   
2. While going through the book, I noticed that it covered some topics such as Annotations and Security, that are not present on the OCP Java 17 exam anymore. They were there on the older Java 11 exam. I enquired about it with the authors and learned that they included these topics partly because they felt they were important and partly to make the book useful for candidates taking the OCP Java 11 (Exam Code 1Z0-819) exam.
   
   
3. Complicated concepts such as Generics have been taught thoroughly. For example, students find it confusing that Node<Integer> and Node<Double> are not subtypes of Node<Number> even though Integer and Double are subtypes of Number. Concurrency and parallalism is another tough topic to grasp. The book explains all such topics in great detail.
   
   
4. The chapters are peppered with objective questions, and at the end there is a full sized mock exam with detailed explanations for all of the questions.
   
   
5. If you are short on time and want to just focus on passing the exam in the shortest time possible, then you may have to look for other resources because the book does include topics that are not required for the exam at all. For example, Appendix G on the Java Logging API can be skipped. But in all fairness, the official exam objectives do mention it in passing. We haven't prepared a complete list of such topics, but we might do that later as we start using the book in our training program.