Oracle Java

This section groups Oracle Java developer exam guides. These pages are code-reading first: compile-time legality, type inference, object model rules, collections, streams, modules, concurrency, I/O, localization, and modern Java feature boundaries.

Published Java Guides

For Java exams, do not start by predicting output. First decide whether the code compiles, then resolve the declared types, overloads, generic bounds, exception rules, and API contracts.

In this section

• Oracle Java 17 1Z0-829 Guide: Java SE 17 Developer
  Oracle Java 1Z0-829 exam guide covering Java 17 language behavior, flow, objects, collections, streams, and concurrency decisions.
  • 1Z0-829 Java 17 Language Fundamentals and Type System Guide
    Study 1Z0-829 Java 17 Language Fundamentals and Type System: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Primitives, Wrappers, var, Casting and Operators Guide
      Study 1Z0-829 Java 17 Primitives, Wrappers, var, Casting and Operators: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Control Flow and Exceptions Guide
    Study 1Z0-829 Java 17 Control Flow and Exceptions: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Selection, Switch, Exceptions and Assertions Guide
      Study 1Z0-829 Java 17 Selection, Switch, Exceptions and Assertions: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 OOP and Inheritance Guide
    Study 1Z0-829 Java 17 OOP and Inheritance: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Classes, Interfaces, and Inheritance Guide
      Study 1Z0-829 Java 17 Classes, Interfaces, and Inheritance: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Encapsulation and Object Model Guide
    Study 1Z0-829 Java 17 Encapsulation and Object Model: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Access, Immutability, and Object Contracts Guide
      Study 1Z0-829 Java 17 Access, Immutability, and Object Contracts: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Generics and Collections Framework Guide
    Study 1Z0-829 Java 17 Generics and Collections Framework: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Wildcards, Collections, and Algorithms Guide
      Study 1Z0-829 Java 17 Wildcards, Collections, and Algorithms: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Functional Programming Guide
    Study 1Z0-829 Java 17 Functional Programming: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Lambdas and Method References Guide
      Study 1Z0-829 Java 17 Lambdas and Method References: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Streams and Optional Guide
    Study 1Z0-829 Java 17 Streams and Optional: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Streams, Collectors, and Optional Guide
      Study 1Z0-829 Java 17 Streams, Collectors, and Optional: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Modern Java 17 Features Guide
    Study 1Z0-829 Java 17 Modern Java 17 Features: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Records, Sealed Types, Switch, and Text Blocks Guide
      Study 1Z0-829 Java 17 Records, Sealed Types, Switch, and Text Blocks: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Java Platform Module System Guide
    Study 1Z0-829 Java 17 Java Platform Module System: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 JPMS, Services, Module Path and Migration Guide
      Study 1Z0-829 Java 17 JPMS, Services, Module Path and Migration: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Concurrency Basics Guide
    Study 1Z0-829 Java 17 Concurrency Basics: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Threads, Executors, and CompletableFuture Guide
      Study 1Z0-829 Java 17 Threads, Executors, and CompletableFuture: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 I/O, NIO.2 and HTTP Client Guide
    Study 1Z0-829 Java 17 I/O, NIO.2 and HTTP Client: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Paths, Files, Buffered I/O and HTTP Client Guide
      Study 1Z0-829 Java 17 Paths, Files, Buffered I/O and HTTP Client: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Date/Time API Guide
    Study 1Z0-829 Java 17 Date/Time API: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Core Temporal Types, Zones and Formatting Guide
      Study 1Z0-829 Java 17 Core Temporal Types, Zones and Formatting: key concepts, common traps, and exam decision cues.
  • 1Z0-829 Java 17 Annotations, Reflection and Packaging Guide
    Study 1Z0-829 Java 17 Annotations, Reflection and Packaging: key concepts, common traps, and exam decision cues.
    • 1Z0-829 Java 17 Annotations, Reflection, and Tools Guide
      Study 1Z0-829 Java 17 Annotations, Reflection, and Tools: key concepts, common traps, and exam decision cues.
  • Java 17 1Z0-829 Study Plan: 30, 60, and 90 Days
    Java 17 1Z0-829 30-, 60-, and 90-day study plan with topic order, review loops, and final-week priorities.
  • Java 17 1Z0-829 Cheat Sheet: Developer Traps
    Java 17 1Z0-829 cheat sheet for Java developer traps, APIs, code reading, and final review.
  • Java 17 1Z0-829 Sample Questions with Explanations
    Java 17 1Z0-829 sample questions with explanations, traps, and topic labels.
  • Java 17 1Z0-829 FAQ: Exam Format and Prep
    Java 17 1Z0-829 FAQ for exam format, topics, prep strategy, practice, and common candidate traps.
  • Java 17 1Z0-829 Resources: Official Links and Study Tools
    Java 17 1Z0-829 resources for official links, blueprint checks, study tools, and source review.
  • Java 17 1Z0-829 Glossary: Key Terms
    Oracle Java 1Z0-829 glossary of Java 17 language, flow, objects, collections, streams, and concurrency terms.
• Oracle Java 21 1Z0-830 Guide: Java SE 21 Developer Professional
  Oracle Java 1Z0-830 exam guide covering Java 21 language behavior, collections, streams, modules, and concurrency decisions.
  • 1Z0-830 Java 21 Types, Operators and Text Guide
    Study 1Z0-830 Java 21 Types, Operators and Text: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Conversions, Strings, Operators, and var Guide
      Study 1Z0-830 Java 21 Conversions, Strings, Operators, and var: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Date/Time API Guide
    Study 1Z0-830 Java 21 Date/Time API: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Core Types, Zones, Manipulation and DST Guide
      Study 1Z0-830 Java 21 Core Types, Zones, Manipulation and DST: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Control Flow Guide
    Study 1Z0-830 Java 21 Control Flow: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Loops, Switch and Pattern Matching Guide
      Study 1Z0-830 Java 21 Loops, Switch and Pattern Matching: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 OOP and Object Model Guide
    Study 1Z0-830 Java 21 OOP and Object Model: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Classes, Records, and Object Contracts Guide
      Study 1Z0-830 Java 21 Classes, Records, and Object Contracts: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Inheritance and Polymorphism Guide
    Study 1Z0-830 Java 21 Inheritance and Polymorphism: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Sealed Types and Overrides Guide
      Study 1Z0-830 Java 21 Sealed Types and Overrides: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Interfaces and Enums Guide
    Study 1Z0-830 Java 21 Interfaces and Enums: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Interfaces, Default Methods, and Enums Guide
      Study 1Z0-830 Java 21 Interfaces, Default Methods, and Enums: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Exceptions Guide
    Study 1Z0-830 Java 21 Exceptions: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Exceptions and Try-with-Resources Guide
      Study 1Z0-830 Java 21 Exceptions and Try-with-Resources: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Arrays and Collections Guide
    Study 1Z0-830 Java 21 Arrays and Collections: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Collections and Mutability Traps Guide
      Study 1Z0-830 Java 21 Collections and Mutability Traps: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Generics Guide
    Study 1Z0-830 Java 21 Generics: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Type Parameters, Bounds, Wildcards and Erasure Guide
      Study 1Z0-830 Java 21 Type Parameters, Bounds, Wildcards and Erasure: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Lambdas, Streams and Collectors Guide
    Study 1Z0-830 Java 21 Lambdas, Streams and Collectors: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Streams, Collectors, and Debugging Guide
      Study 1Z0-830 Java 21 Streams, Collectors, and Debugging: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Modules and Packaging Guide
    Study 1Z0-830 Java 21 Modules and Packaging: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 JPMS, Services, JARs and Runtime Packaging Guide
      Study 1Z0-830 Java 21 JPMS, Services, JARs and Runtime Packaging: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Concurrency Guide
    Study 1Z0-830 Java 21 Concurrency: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Virtual Threads and Concurrency Guide
      Study 1Z0-830 Java 21 Virtual Threads and Concurrency: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 I/O, NIO.2 and Serialization Guide
    Study 1Z0-830 Java 21 I/O, NIO.2 and Serialization: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Files, Paths, Streams and Serialization Safety Guide
      Study 1Z0-830 Java 21 Files, Paths, Streams and Serialization Safety: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Localization Guide
    Study 1Z0-830 Java 21 Localization: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Locales, Resource Bundles and Formatting Guide
      Study 1Z0-830 Java 21 Locales, Resource Bundles and Formatting: key concepts, common traps, and exam decision cues.
  • 1Z0-830 Java 21 Annotations and Logging Guide
    Study 1Z0-830 Java 21 Annotations and Logging: key concepts, common traps, and exam decision cues.
    • 1Z0-830 Java 21 Annotations and JUL Essentials Guide
      Study 1Z0-830 Java 21 Annotations and JUL Essentials: key concepts, common traps, and exam decision cues.
  • Java 21 1Z0-830 Study Plan: Streams, Concurrency, and Modern Java in 30, 60, and 90 Days
    Java 21 1Z0-830 30-, 60-, and 90-day study plan for streams, concurrency, modern Java, review loops, and final-week priorities.
  • Java 21 1Z0-830 Cheat Sheet: Developer Traps
    Java 21 1Z0-830 cheat sheet for Java developer traps, APIs, code reading, and final review.
  • Java 21 1Z0-830 Sample Questions with Explanations
    Java 21 1Z0-830 sample questions with explanations, traps, and topic labels.
  • Java 21 1Z0-830 FAQ: Exam Format and Prep
    Java 21 1Z0-830 FAQ for exam format, topics, prep strategy, practice, and common candidate traps.
  • Java 21 1Z0-830 Resources: Docs, JDK Guides, and Official Links
    Java 21 1Z0-830 resources for docs, JDK guides, official links, and source review.
  • Java 21 1Z0-830 Glossary: Key Terms
    Oracle Java 1Z0-830 glossary of Java 21 language, flow, collections, modules, and concurrency terms.
• Oracle Java 25 1Z0-831 Guide: Java SE 25 Developer Professional
  Oracle Java 1Z0-831 exam guide covering Java 25 language behavior, constructors, collections, streams, and concurrency decisions.
  • 1Z0-831 Java 25 Core Guide
    Study 1Z0-831 Java 25 Core: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Conversions, Text, and Inference Guide
      Study 1Z0-831 Java 25 Conversions, Text, and Inference: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Flow Guide
    Study 1Z0-831 Java 25 Flow: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Patterns, switch, and Branch Legality Guide
      Study 1Z0-831 Java 25 Patterns, switch, and Branch Legality: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Constructors Guide
    Study 1Z0-831 Java 25 Constructors: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Classes, Records, and Constructors Guide
      Study 1Z0-831 Java 25 Classes, Records, and Constructors: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Inheritance Guide
    Study 1Z0-831 Java 25 Inheritance: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Sealed Types, Interfaces, and Enums Guide
      Study 1Z0-831 Java 25 Sealed Types, Interfaces, and Enums: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Collections Guide
    Study 1Z0-831 Java 25 Collections: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Collections, Ordering, and Generic Bounds Guide
      Study 1Z0-831 Java 25 Collections, Ordering, and Generic Bounds: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Streams Guide
    Study 1Z0-831 Java 25 Streams: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Streams, Collectors, and Gatherers Guide
      Study 1Z0-831 Java 25 Streams, Collectors, and Gatherers: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Concurrency Guide
    Study 1Z0-831 Java 25 Concurrency: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Virtual Threads and Structured Concurrency Guide
      Study 1Z0-831 Java 25 Virtual Threads and Structured Concurrency: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Modules Guide
    Study 1Z0-831 Java 25 Modules: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 JPMS, Packaging, and Launch Model Guide
      Study 1Z0-831 Java 25 JPMS, Packaging, and Launch Model: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 I/O Guide
    Study 1Z0-831 Java 25 I/O: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Files, Paths, Formatting, and Localization Guide
      Study 1Z0-831 Java 25 Files, Paths, Formatting, and Localization: key concepts, common traps, and exam decision cues.
  • 1Z0-831 Java 25 Exceptions Guide
    Study 1Z0-831 Java 25 Exceptions: key concepts, common traps, and exam decision cues.
    • 1Z0-831 Java 25 Exceptions, Resource Handling, and Logging Guide
      Study 1Z0-831 Java 25 Exceptions, Resource Handling, and Logging: key concepts, common traps, and exam decision cues.
  • Java 25 1Z0-831 Study Plan: 30, 60, and 90 Days
    Java 25 1Z0-831 30-, 60-, and 90-day study plan with topic order, review loops, and final-week priorities.
  • Java 25 1Z0-831 Cheat Sheet
    Java 25 1Z0-831 cheat sheet for key facts, traps, service mappings, and final review.
  • Java 25 1Z0-831 FAQ: Exam Format and Prep
    Java 25 1Z0-831 FAQ for exam format, topics, prep strategy, practice, and common candidate traps.
  • Java 25 1Z0-831 Resources: Official Links and Study Tools
    Java 25 1Z0-831 resources for official links, blueprint checks, study tools, and source review.
  • Java 25 1Z0-831 Glossary: Key Terms
    Oracle Java 1Z0-831 glossary of Java 25 language, constructors, streams, modules, and concurrency terms.