1Z0-830 study guide · 2026

The 10 1Z0-830 domains, explained

10 areas and 24 objectives. Oracle does not publish weights for these areas, so each gets equal space here. Each guide explains what the area covers, how it is assessed and where candidates slip.

Start with Domain 1 See all domains
Questions
50
Time
120 minutes
Passing score
68%
Outline
1Z0-830 exam topics (Oracle, published July 2024; current, read via secondary reproduction)

Exam blueprint

Oracle does not publish weights, so every area is drawn the same size.

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  1. 1 Handling Date, Time, Text, Numeric and Boolean Values
  2. 2 Controlling Program Flow
  3. 3 Using Object-Oriented Concepts in Java
  4. 4 Handling Exceptions
  5. 5 Working with Arrays and Collections
  6. 6 Working with Streams and Lambda expressions
  7. 7 Packaging and Deploying Java Code
  8. 8 Managing Concurrent Code Execution
  9. 9 Using Java I/O API
  10. 10 Implementing Localization

All 10 domains

24 official objectives 71–95 hrs suggested study

  1. Domain 01

    Handling Date, Time, Text, Numeric and Boolean Values

    This section tests the core value types of Java 21: primitives and their wrappers, arithmetic and boolean expressions, String and StringBuilder methods including text blocks, and the java.time classes for dates, durations, periods, instants and time zones.

    Inside this domain

    • 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.

    Watch for Boxed equality

    Objectives
    3
    Questions est.
    ~6
    Study time est.
    8–10 hrs
  2. Domain 02

    Controlling Program Flow

    This section covers the constructs that decide which Java code runs and how often: if/else chains, switch statements and switch expressions, for, enhanced for, while and do/while loops, and break and continue with or without labels.

    Inside this domain

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

    Watch for Arrow fall-through

    Objectives
    1
    Questions est.
    ~4
    Study time est.
    4–6 hrs
  3. Domain 03

    Using Object-Oriented Concepts in Java

    The largest section of 1Z0-830 covers object creation and lifecycle, classes and records, initializers, overloading, scope and immutability, inheritance with abstract and sealed types, polymorphism and pattern matching, interfaces, and enums with fields and constructors.

    Inside this domain

    • 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.
    • and 3 more objectives

    Watch for Polymorphic fields

    Objectives
    7
    Questions est.
    ~10
    Study time est.
    14–18 hrs
  4. Domain 04

    Handling Exceptions

    This section tests how Java code reports and recovers from errors: checked and unchecked exceptions, try/catch/finally flow, try-with-resources and suppressed exceptions, multi-catch rules, and writing your own exception classes.

    Inside this domain

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

    Watch for Close after catch

    Objectives
    1
    Questions est.
    ~4
    Study time est.
    5–7 hrs
  5. Domain 05

    Working with Arrays and Collections

    This section covers storing and organizing data in Java 21: creating and copying arrays, using List, Set, Map and Deque implementations, adding, removing, updating and retrieving elements, and sorting with Comparable and Comparator.

    Inside this domain

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

    Watch for Remove by value

    Objectives
    1
    Questions est.
    ~5
    Study time est.
    6–8 hrs
  6. Domain 06

    Working with Streams and Lambda expressions

    This section covers functional-style Java: lambda expressions and method references, the built-in functional interfaces, object and primitive streams, intermediate and terminal operations, Optional, reduction, and grouping and partitioning with Collectors on sequential and parallel streams.

    Inside this domain

    • 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.

    Watch for Missing terminal operation

    Objectives
    2
    Questions est.
    ~7
    Study time est.
    10–14 hrs
  7. Domain 07

    Packaging and Deploying Java Code

    This section covers the Java Platform Module System and deployment: writing module-info.java, exporting and opening packages, declaring dependencies and services, compiling and running modular code, building jars and runtime images, and migrating with unnamed and automatic modules.

    Inside this domain

    • 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.

    Watch for Export the implementation

    Objectives
    2
    Questions est.
    ~3
    Study time est.
    6–8 hrs
  8. Domain 08

    Managing Concurrent Code Execution

    This section covers running Java code concurrently: creating platform and virtual threads, Runnable and Callable tasks, thread lifecycle, executor services, locks and atomic variables for thread safety, concurrent collections, and parallel streams.

    Inside this domain

    • 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.

    Watch for Fixed total

    Objectives
    3
    Questions est.
    ~5
    Study time est.
    8–10 hrs
  9. Domain 09

    Using Java I/O API

    This section covers reading and writing data in Java 21: byte and character I/O streams, console input and output, serializing and deserializing objects, and building, navigating, creating, reading and writing files with Path and Files from java.nio.file.

    Inside this domain

    • 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.

    Watch for Constructor runs on read

    Objectives
    3
    Questions est.
    ~4
    Study time est.
    6–8 hrs
  10. Domain 10

    Implementing Localization

    This section covers adapting Java programs to different languages and regions: creating Locale objects, loading resource bundles and their fallback order, and parsing and formatting messages, dates, times, numbers, currency and percentages for a locale.

    Inside this domain

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

    Watch for Default locale first

    Objectives
    1
    Questions est.
    ~2
    Study time est.
    4–6 hrs

Suggested study order

No official weights are published, so follow the outline order, across about 71–95 hrs of study.

  1. 1 Handling Date, Time, Text, Numeric and Boolean Values 8–10 hrs
  2. 2 Controlling Program Flow 4–6 hrs
  3. 3 Using Object-Oriented Concepts in Java 14–18 hrs
  4. 4 Handling Exceptions 5–7 hrs
  5. 5 Working with Arrays and Collections 6–8 hrs
  6. 6 Working with Streams and Lambda expressions 10–14 hrs
  7. 7 Packaging and Deploying Java Code 6–8 hrs
  8. 8 Managing Concurrent Code Execution 8–10 hrs
  9. 9 Using Java I/O API 6–8 hrs
  10. 10 Implementing Localization 4–6 hrs

Try one

Practice questionDomain 1: Handling Date, Time, Text, Numeric and Boolean Values

A billing job extends a subscription by one month and adds a grace day. What does this code print? LocalDate d = LocalDate.of(2024, 1, 31); d.plusMonths(1); d = d.plusMonths(1).plusDays(1); System.out.println(d);

One trap from every domain

The answer that looks right, and the clue that gives it away.

  • Domain 1

    Boxed equality

    Clue A boxed value above 127 compared with ==.

  • Domain 2

    Arrow fall-through

    Clue Cases written as case 2 -> with no break statements.

  • Domain 3

    Polymorphic fields

    Clue Same-named fields in parent and child classes.

  • Domain 4

    Close after catch

    Clue Resources that print inside close().

  • Domain 5

    Remove by value

    Clue A List<Integer> with remove called on an int literal.

  • Domain 6

    Missing terminal operation

    Clue A pipeline that ends with map or filter.

  • Domain 7

    Export the implementation

    Clue A provides ... with directive already present.

  • Domain 8

    Fixed total

    Clue A shared int field updated without synchronization or atomics.

Practise what you read

1Z0-830 domains: common questions

How many domains are in the 1Z0-830 exam?

1Z0-830 has 10 domains with 24 official objectives between them: Handling Date, Time, Text, Numeric and Boolean Values, Controlling Program Flow, Using Object-Oriented Concepts in Java, Handling Exceptions, Working with Arrays and Collections, Working with Streams and Lambda expressions, Packaging and Deploying Java Code, Managing Concurrent Code Execution, Using Java I/O API and Implementing Localization.

What is the 1Z0-830 exam format?

Questions: 50. Time allowed: 120 minutes. Passing score: 68%.

How long should I study for 1Z0-830?

Our planning estimate is 71–95 hrs across all domains, split by weight. It is an editorial estimate, not an official figure, so adjust it to your experience and to how you score on practice questions.

Where should I start?

Work through the areas in order, since each builds on the one before. Use the checklist on each page to confirm you can do what it asks before moving on.

Which outline is this guide based on?

This guide follows 1Z0-830 exam topics (Oracle, published July 2024; current, read via secondary reproduction), published by Oracle. It was last reviewed in October 2026.

Domain names, weights and objectives come from Oracle's official outline (1Z0-830 exam topics (Oracle, published July 2024; current, read via secondary reproduction)). Question counts and study hours are editorial planning estimates, not official figures. Last reviewed October 2026.