What’s New in IntelliJ IDEA 2026.1 EAP? Java 26, Spring Boot 4, Gradle 9 & More

Overview

IntelliJ IDEA 2026.1 EAP adds Java 26 language‑level support, Spring Boot 4 integration, Gradle 9 and Maven 4 support, IDE refinements, and over 600 bug fixes.

1. Language Features – Java 26 and Pattern Matching

1.1 Java 26 Language Level

Provides a preview Java 26 language level for testing upcoming JDK 26 features.

1.2 Primitive‑type Pattern Matching (JEP 530)

Full support for primitive‑type pattern matching eliminates boxing overhead.

// Wrapper type pattern matching (pre‑JEP 530)
if (obj instanceof Integer i) {
    // use i
}

With JEP 530:

Object obj = 42L;
if (obj instanceof long l) {
    System.out.println("Long value: " + l);
}

Pattern matching is also available in switch expressions:

String formatNumber(Object obj) {
    return switch (obj) {
        case byte b   -> "Byte: " + b;
        case short s  -> "Short: " + s;
        case int i    -> "Int: " + i;
        case long l   -> "Long: " + l;
        case float f  -> "Float: " + f;
        case double d -> "Double: " + d;
        default       -> "Unknown type";
    };
}

Benefits

Performance boost – no boxing/unboxing.

Cleaner code – fewer manual conversions.

Type safety – compile‑time checks.

JEP documentation: https://openjdk.org/jeps/530

2. Spring Ecosystem – Spring Boot 4 Support

2.1 Spring Boot 4 Deep Integration

Spring Boot 4.0 (Nov 2025) is fully supported. Highlights include HTTP Service Clients, native API version management, default non‑null JSpecify safety, upgraded dependencies (Jackson 3.0, Tomcat 11, Hibernate 7.1), Gradle 9 support, Redis static master‑slave configuration, and removal of Undertow.

2.2 Spring Data JDBC Enhancements

Sequence support – handling of database sequences, including unnamed sequences.

Kotlin coroutine support – Kotlin DSL now supports coroutine‑based routing in Spring Web.

Embedded prefix – ability to add a prefix to embedded objects.

2.3 Spring Debugger Stability

Transaction node fix – stale nodes removed when no active transaction exists.

Remote debugging enhancement – fixed “Attach Debugger…” unavailability.

Database connection fix – resolved character‑escape error preventing connections.

3. Build Tool Modernization – Gradle 9 & Maven 4

3.1 Gradle 9 Adoption

Gradle 9.0 introduces breaking changes but offers significant performance gains. It requires JVM 17+ for the daemon while still allowing compilation targeting Java 6+. The default execution mode is Configuration Cache, which automatically falls back to non‑cached mode for incompatible tasks.

Key benefits

Graceful degradation – automatic fallback prevents build failures.

≈50 % speed improvement for small module changes.

Progressive migration – tasks can be marked as incompatible with the cache.

Example comparison:

// Gradle 8 – cache optional
tasks.named('compileJava').configure {
    // manual cache compatibility handling
}

// Gradle 9 – cache preferred, automatic fallback
// builds faster and won’t fail due to cache issues

3.2 Kotlin DSL Experience Upgrade

In build.gradle.kts, IDEA now provides UI run‑configuration buttons for tasks registered via tasks.register { } and improved code completion.

// build.gradle.kts
tasks.register("myCustomTask") {
    doLast {
        println("Executing custom task")
    }
}
// In IDEA 2026.1 EAP the task appears automatically in the Run Configurations panel.

3.3 Maven 4 Integration

Built‑in Maven version upgraded to 4.0.0‑rc‑5 .

Sync improvements – fixed failure when <subprojects> element is used under Maven 4.0.0 model.

4. Development Experience Optimizations

4.1 Lombok Plugin Enhancements

Support for @Accessors(fluent = true) – generates fluent getter/setter methods.

Builder method parsing fix – resolves cases where builder methods were not correctly recognized.

New error check – using @Slf4j on non‑static inner classes now produces a compilation error.

// Incorrect usage – compilation error
class Outer {
    @Slf4j // ❌ error: @Slf4j cannot be used on non‑static inner class
    class Inner {}
}

// Correct usage – static inner class
class Outer {
    static class Inner {
        @Slf4j // ✅ OK
    }
}

4.2 Framework and Language Fixes

Hibernate plugin regression fixed – no longer requires Spring plugin as a prerequisite.

Groovy 5 support – corrected false error reports for static interface methods.

JPA QL syntax – fixed highlighting for RIGHT JOIN and coalesce subqueries.

4.3 Javadoc‑to‑Markdown Conversion

The “Convert to Markdown documentation comment” action now preserves line breaks and list indentation correctly.

5. Performance & Stability – 600+ Bug Fixes

5.1 Core Platform

WSL Tomcat debugging – fixed non‑working debugging in Windows Subsystem for Linux.

Remote development freezes – resolved several freezing issues.

5.2 UI Improvements

Editor responsiveness – smoother editing experience.

Terminal – various stability fixes.

Search – faster and more accurate results.

5.3 Language Support Enhancements

Kotlin – continued IDE optimizations.

Groovy – better script editing experience.

JavaScript/TypeScript – enhanced front‑end language support.

6. Upgrade Recommendation

For developers experimenting with Spring Boot 4 or Java 26 preview features, the IntelliJ IDEA 2026.1 EAP provides early access. Because this is an EAP build, use it only in non‑production environments and back up your configuration regularly.

References

Release notes: https://youtrack.jetbrains.com/articles/IDEA-A-2100662609/IntelliJ-IDEA-2026-1-EAP-1-261-17801.55-build-Release-Notes

Gradle 9.0 new features: https://gradle.org/whats-new/gradle-9