eBook – Guide Spring Cloud – NPI EA (cat=Spring Cloud)
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Let's get started with a Microservice Architecture with Spring Cloud:

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eBook – Mockito – NPI EA (tag = Mockito)
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Mocking is an essential part of unit testing, and the Mockito library makes it easy to write clean and intuitive unit tests for your Java code.

Get started with mocking and improve your application tests using our Mockito guide:

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eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
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Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.

Get started with understanding multi-threaded applications with our Java Concurrency guide:

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eBook – Reactive – NPI EA (cat=Reactive)
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Spring 5 added support for reactive programming with the Spring WebFlux module, which has been improved upon ever since. Get started with the Reactor project basics and reactive programming in Spring Boot:

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eBook – Java Streams – NPI EA (cat=Java Streams)
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Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.

But these can also be overused and fall into some common pitfalls.

To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:

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eBook – Jackson – NPI EA (cat=Jackson)
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Do JSON right with Jackson

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eBook – HTTP Client – NPI EA (cat=Http Client-Side)
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Get the most out of the Apache HTTP Client

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eBook – Maven – NPI EA (cat = Maven)
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Get Started with Apache Maven:

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eBook – Persistence – NPI EA (cat=Persistence)
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Working on getting your persistence layer right with Spring?

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eBook – RwS – NPI EA (cat=Spring MVC)
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Building a REST API with Spring?

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Course – LS – NPI EA (cat=Jackson)
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Get started with Spring and Spring Boot, through the Learn Spring course:

>> LEARN SPRING
Course – RWSB – NPI EA (cat=REST)
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Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:

>> The New “REST With Spring Boot”

Course – LSS – NPI EA (cat=Spring Security)
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Yes, Spring Security can be complex, from the more advanced functionality within the Core to the deep OAuth support in the framework.

I built the security material as two full courses - Core and OAuth, to get practical with these more complex scenarios. We explore when and how to use each feature and code through it on the backing project.

You can explore the course here:

>> Learn Spring Security

Course – LSD – NPI EA (tag=Spring Data JPA)
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Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.

Get started with Spring Data JPA through the guided reference course:

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Partner – Moderne – NPI EA (cat=Spring Boot)
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Refactor Java code safely — and automatically — with OpenRewrite.

Refactoring big codebases by hand is slow, risky, and easy to put off. That’s where OpenRewrite comes in. The open-source framework for large-scale, automated code transformations helps teams modernize safely and consistently.

Each month, the creators and maintainers of OpenRewrite at Moderne run live, hands-on training sessions — one for newcomers and one for experienced users. You’ll see how recipes work, how to apply them across projects, and how to modernize code with confidence.

Join the next session, bring your questions, and learn how to automate the kind of work that usually eats your sprint time.

Course – LJB – NPI EA (cat = Core Java)
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Code your way through and build up a solid, practical foundation of Java:

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1. Overview

ZonedDateTime and OffsetDateTime are pretty popular classes in the Java 8 DateTime API. Furthermore, both store an instant on the timeline up to a precision of nanoseconds. And, at first, it may get confusing to choose between them.

In this quick tutorial, we’re going to look at the differences between ZonedDateTime and OffsetDateTime.

2. ZonedDateTime

A ZonedDateTime is an immutable representation of a date-time with a timezone in the ISO-8601 calendar system, such as 2007-12-03T10:15:30+01:00 Europe/Paris. It holds state equivalent to three separate objects: a LocalDateTime, a ZoneId, and the resolved ZoneOffset

Here, the ZoneId determines how and when the offset changes. So, the offset can’t be freely set, as the zone controls which offsets are valid.

To get the current ZonedDateTime for a specific region, we’ll use:

ZoneId zone = ZoneId.of("Europe/Berlin");
ZonedDateTime zonedDateTime = ZonedDateTime.now(zone);

The ZonedDateTime class also provides built-in methods for converting a given date from one timezone to another:

ZonedDateTime destZonedDateTime = sourceZonedDateTime.withZoneSameInstant(destZoneId);

Finally, it’s fully DST-aware and handles daylight saving time adjustments. It often comes in handy when we want to display a date-time field in a specific timezone.

3. OffsetDateTime

An OffsetDateTime is an immutable representation of a date-time with an offset from UTC/Greenwich in the ISO-8601 calendar system, such as 2007-12-03T10:15:30+01:00. In other words, it stores all date and time fields, to a precision of nanoseconds, as well as the offset from GMT/UTC.

Let’s get the current OffsetDateTime with a two-hour offset from GMT/UTC:

ZoneOffset zoneOffSet= ZoneOffset.of("+02:00");
OffsetDateTime offsetDateTime = OffsetDateTime.now(zoneOffSet);

4. The Main Differences

First, it doesn’t make sense (without conversions) to directly compare two dates with full timezone information. Therefore, we should always prefer storing OffsetDateTime in the database over the ZonedDateTime, as dates with a local time offset always represent the same instants in time.

Moreover, unlike with the ZonedDateTime, adding an index over a column storing the OffsetDateTime won’t change the meaning of the date.

Let’s quickly sum up the key differences.

ZonedDateTime:

  • stores all date and time fields, to a precision of nanoseconds, and a timezone, with a zone offset used to handle ambiguous local date-times
  • can’t freely set offsets, as the zone controls the valid offset values
  • is fully DST-aware and handles daylight savings adjustments
  • comes in handy for displaying date-time fields in a user-specific timezone

OffsetDateTime:

  • stores all date and time fields, to a precision of nanoseconds, as well as the offset from GMT/UTC (no timezone information)
  • should be used for storing a date in the database or communicating it over a network

5. Conclusion

In this tutorial, we covered the differences between the ZonedDateTime and the OffsetDateTime.

The code backing this article is available on GitHub. Once you're logged in as a Baeldung Pro Member, start learning and coding on the project.
Baeldung Pro – NPI EA (cat = Baeldung)
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Baeldung Pro comes with both absolutely No-Ads as well as finally with Dark Mode, for a clean learning experience:

>> Explore a clean Baeldung

Once the early-adopter seats are all used, the price will go up and stay at $33/year.

eBook – HTTP Client – NPI EA (cat=HTTP Client-Side)
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The Apache HTTP Client is a very robust library, suitable for both simple and advanced use cases when testing HTTP endpoints. Check out our guide covering basic request and response handling, as well as security, cookies, timeouts, and more:

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eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
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Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.

Get started with understanding multi-threaded applications with our Java Concurrency guide:

>> Download the eBook

eBook – Java Streams – NPI EA (cat=Java Streams)
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Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.

But these can also be overused and fall into some common pitfalls.

To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:

>> Join Pro and download the eBook

eBook – Persistence – NPI EA (cat=Persistence)
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Working on getting your persistence layer right with Spring?

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Course – LS – NPI EA (cat=REST)

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Get started with Spring Boot and with core Spring, through the Learn Spring course:

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Partner – Moderne – NPI EA (tag=Refactoring)
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Modern Java teams move fast — but codebases don’t always keep up. Frameworks change, dependencies drift, and tech debt builds until it starts to drag on delivery. OpenRewrite was built to fix that: an open-source refactoring engine that automates repetitive code changes while keeping developer intent intact.

The monthly training series, led by the creators and maintainers of OpenRewrite at Moderne, walks through real-world migrations and modernization patterns. Whether you’re new to recipes or ready to write your own, you’ll learn practical ways to refactor safely and at scale.

If you’ve ever wished refactoring felt as natural — and as fast — as writing code, this is a good place to start.

eBook Jackson – NPI EA – 3 (cat = Jackson)