Best of Java — November 2025

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   Article

   Spring·23w

   Null-Safe applications with Spring Boot 4

   Spring Boot 4 and the Spring portfolio now provide null-safe APIs using JSpecify annotations to help prevent NullPointerExceptions. The Spring team has annotated most major projects including Spring Framework 7, Spring Data 4, and Spring Security 7 with explicit nullability information. Developers can leverage this through IDE support (IntelliJ IDEA 2025.3+) for warnings, or use build-time checkers like NullAway for stricter enforcement. Kotlin 2 automatically translates these annotations to native Kotlin nullability. This allows teams to choose their level of null-safety adoption, from simple IDE warnings to fully null-safe applications, without breaking existing APIs.

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   Article

   A Java geek·22w

   Are you really wasting your time in Java without these 10 libraries?

   A critical analysis of 10 commonly recommended Java libraries, evaluating their current relevance and usefulness. The author argues that some popular tools like Lombok and MapStruct are no longer necessary given modern Java features and alternatives like Kotlin, while others like Liquibase/Flyway remain essential for production deployments. The piece emphasizes context-dependent decision-making over blindly following listicles, noting that tools like SLF4J, Jackson, JUnit, and Spring remain valuable, while Apache Commons Lang and Guava have diminished utility in modern Java versions.

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   Article

   Javarevisited·23w

   Why I Implemented a Custom Serializer/Deserializer for JJWT Instead of Using jjwt-jackson

   A developer explains their decision to build a custom JSON serializer/deserializer for JWT handling instead of using the popular Jackson library. The custom implementation reduces security vulnerabilities from external dependencies, maintains framework consistency with existing tooling, provides better control over predictable JWT payloads, and eliminates unnecessary complexity. The lightweight codec integrates seamlessly with JJWT through its SPI mechanism while keeping the codebase transparent and maintainable.

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   Article

   InfoWorld·23w

   C# rises in Tiobe language popularity index

   C# has become the fastest-growing language on Tiobe's popularity index with a 7.65% rating, gaining 2.67 percentage points year-over-year. The language now trails Java by less than one percentage point and could overtake it for the first time, driven by its cross-platform capabilities, open source nature, and Microsoft's strong backing. Python continues to lead the index at 23.37%, though its growth has plateaued. C# is a strong contender for Tiobe's 2025 Language of the Year award.

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   Article

   JetBrains·21w

   Spring Boot 4: Leaner, Safer Apps and a New Kotlin Baseline

   Spring Boot 4.0 introduces significant improvements including better modularization for reduced memory usage, JSpecify as the standard null-safety library, and enhanced observability with Micrometer. The release establishes Kotlin 2.2 as the official baseline, bringing native JSpecify annotation support, cleaner API versioning, and more elegant bean registration through Kotlin DSL. IntelliJ IDEA 2025.3 provides full support for these features with compiler warnings and IDE inspections for null-safety violations.

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   Article

   Vespa Blog·23w

   LLMs, Vespa, and a side of Summer Debugging

   Two interns built an MCP (Model Context Protocol) server for Vespa, starting with a Python prototype using PyVespa and the MCP SDK, then rewrote it in Java for full container integration. The server enables LLMs to query Vespa applications using natural language through three main tools: schema retrieval, documentation search, and query execution. Key challenges included implementing custom request handlers, managing stateless communication across distributed nodes, and adapting to frequent MCP SDK updates. The final implementation runs as a Vespa component with HTTP transport, providing read-only access to applications both locally and in the cloud.

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   Article

   Neil Madden·23w

   Were URLs a bad idea?

   Explores the evolution of URL handling in Java, questioning whether generic URL APIs like URL.openConnection() were a good design choice. The author argues that Java 11's HttpClient, being protocol-specific rather than generic, represents better API design. Generic URL handling introduces security risks, performance unpredictability, and forces lowest-common-denominator APIs. Modern applications typically handle a single URL scheme and benefit from specialized, focused implementations rather than attempting universal URL support.

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   Article

   Spring·24w

   Spring gRPC Next Steps for 1.0.0

   Spring gRPC 1.0 will support Spring Boot 4.0 as a standalone project rather than being merged into Spring Boot 4.0 as originally planned. The autoconfiguration merge is now targeted for Spring Boot 4.1. Users can upgrade from version 0.12.0 by simply changing the version number in their dependency management, with minimal code changes required. The autoconfiguration and starter dependencies will be deprecated immediately upon release to signal the planned migration to Spring Boot 4.1, though this deprecation is purely about dependency coordinate changes.

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   Article

   Spring·21w

   Towards Spring Tools 5 - Ready for Boot 4 and Framework 7

   Spring Tools 5 is scheduled for GA release on December 10th with support for Spring Framework 7 and Spring Boot 4. Key features include API versioning support with code lenses and validation, recognition of functional bean definitions via the new bean registrar API, visualization of AOT-compiled Spring Data repository queries with SQL preview, and automatic configuration for JSpecify null analysis annotations. The tooling enhancements work across Eclipse, Visual Studio Code, Cursor, and Theia environments.

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    Article

    Foojay.io·22w

    Document Your Spring REST APIs with Annotations

    Learn how to document Spring REST APIs using Swagger/OpenAPI annotations like @Tag, @Operation, @Parameter, @ApiResponse, and @Schema. These annotations keep API documentation synchronized with code, making endpoints self-documenting and easier to maintain. The guide includes practical examples of annotating controllers and DTOs, explains why documentation matters for team onboarding and client integrations, and provides a step-by-step approach to gradually adding documentation to existing APIs.

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    Article

    Javarevisited·24w

    Top 10 YouTube Channels to Follow for Java in 2025

    A curated list of 10 YouTube channels for learning Java in 2025, ranging from official sources like the Java and Spring channels to educational creators like Java Brains, in28minutes, and Programming with Mosh. The list covers resources for all skill levels, from absolute beginners to advanced developers, with channels focusing on core Java, Spring ecosystem, microservices, backend development, and cloud integration. Each recommendation includes the channel's purpose and target audience.

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    Article

    InfoQ·21w

    Spring Framework 7 and Spring Boot 4 Deliver API Versioning, Resilience, and Null-Safe Annotations

    Spring Framework 7.0 and Spring Boot 4.0 introduce first-class REST API versioning with multiple strategies (path, header, query, media type), standardized null safety through JSpecify annotations, and built-in resilience features like retry and concurrency throttling. The releases migrate to Jackson 3 for JSON processing, modularize Spring Boot's autoconfiguration into technology-specific modules, and maintain JDK 17 baseline while supporting JDK 25. New baselines include Jakarta EE 11 and Kotlin 2.2. Additional improvements include HTTP Interface Groups, multi-factor authentication in Spring Security 7, GraalVM Native Image optimizations, and coordinated releases across the Spring ecosystem.

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    Article

    Javarevisited·23w

    Top 5 Frontend Masters Courses to Learn Java and Spring Boot in 2026

    A curated list of five Frontend Masters courses for learning Java and Spring Boot development. The selection includes Java fundamentals with Angie Jones, enterprise Spring Boot with Josh Long, web development basics, API design principles, and SQL with PostgreSQL. Each course is described with learning outcomes, instructor credentials, and target audience, along with a recommended 22-week learning path for progressing from beginner to professional-grade enterprise development.

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    Article

    A Java geek·24w

    Choosing a dependency

    A comprehensive framework for evaluating software dependencies before adding them to your project. Covers critical decision criteria including licensing, governance models, project maturity indicators, community activity metrics, support options, developer experience, and market adoption. Emphasizes treating dependency selection as a risk management exercise with ongoing monitoring rather than a one-time decision.

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    Article

    Baeldung·20w

    Reduce Object Header Size and Save Memory in Java 25

    Java 25 introduces JEP 519, which makes Compact Object Headers a production feature in HotSpot JVM. This reduces object header size from 96-128 bits to 64 bits on 64-bit platforms by merging the mark word and class pointer. The change delivers 10-20% memory reduction for applications with many small objects, improves cache utilization, and reduces garbage collection pressure. Benchmarks show 22% heap space reduction and 15% fewer GC cycles in SPECjbb2015 tests. The feature requires compressed class pointers and is not yet supported by JVMCI on x64.

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    Article

    Spring·20w

    Towards Spring Tools 5 - Stereotypes and a new Structural View

    Spring Tools 5 introduces a logical structure view that organizes projects by stereotypes (services, repositories, controllers) rather than files and folders. Built on jMolecules 2.0 concepts, it provides a Spring-centric perspective of codebases, supports Spring Modulith's modular architecture, and allows developers to define custom stereotypes through metadata files or annotations. The view is customizable, letting developers control which stereotype groups appear in the tree structure.

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    Jakarta EE·22w

    SpringBoot 4.0, preview of Jakarta Data 1.1 and more in 25.0.0.12-beta- OpenLiberty.io

    Open Liberty 25.0.0.12-beta introduces Spring Boot 4.x support with JAR and WAR deployment options, requiring Java 17+ and EE11 features. The release previews Jakarta Data 1.1 capabilities including entity projections, the @Is annotation, and Constraint subtype parameters for advanced filtering. Updates to the Model Context Protocol Server 1.0 add session management and improved endpoint discoverability. The Netty-based HTTP transport receives enhancements for HTTP/1.1, HTTP/2, WebSocket, JMS, and SIP communications. A new feature allows developers to provide their own Base64-encoded 256-bit AES keys for password encryption, improving startup performance and preparing for WebSphere migration.

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    Baeldung·20w

    Temporal Workflow Engine with Spring Boot

    Temporal is a workflow engine that enables resilient, deterministic execution of business processes. The Spring Boot integration simplifies setup through automatic workflow and activity registration, declarative worker queue configuration, and auto-configured WorkflowClient beans. The tutorial demonstrates building an order processing workflow with parallel execution, external event handling, timeouts, and failure recovery. Key implementation patterns include using Async.function() for parallel branches, Workflow.await() for blocking on conditions, and signal/query methods for external interaction. The integration supports easy switching between local development, in-memory testing, and production environments through configuration properties.

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    Article

    Spring·22w

    Spring Framework 6.2.13 Available Now

    Spring Framework version 6.2.13 has been released and is now available for download and use in Java applications.

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