Java 25 will be released in September 2025 (PMD 7.18.0 is due end of September 2025).

OpenJDK 25 GA is scheduled for 2025/09/16.

I here list the JEPs I've so far confirmed to be of impact:

• 507: Primitive Types in Patterns, instanceof, and switch (Third Preview)
• 511: Module Import Declarations
• 512: Compact Source Files and Instance Main Methods
• 513: Flexible Constructor Bodies

In summary: https://javaalmanac.io/jdk/25/

This issue is similar to the previous: #5154

EA Release of JDK25 is available here: https://jdk.java.net/25/

Tasks:

• Add new java language versions 25 and 25-preview: net.sourceforge.pmd.lang.java.JavaLanguageModule
  • 25 is the new default
  • update also java.md and ant.md
  • and add in KotlinTestingDsl.kt.
  • Update net.sourceforge.pmd.lang.java.LanguageVersionTest
  • Update net.sourceforge.pmd.lang.java.JavaLanguageModuleTest#previewVersionShouldBeGreaterThanNonPreview
  • Update net.sourceforge.pmd.lang.java.ast.AllJavaAstTreeDumpTest
  • Update net.sourceforge.pmd.dist.BinaryDistributionIT
• Update asm dependency to 9.8 ??:
  • https://search.maven.org/artifact/org.ow2.asm/asm
  • https://asm.ow2.io/versions.html
  • Update net.sourceforge.pmd.lang.java.symbols.internal.asm.AsmSymbolResolver#ASM_API_V if necessary
  • Already updated in 7.13.0 via Bump org.ow2.asm:asm from 9.7.1 to 9.8 #5656
• Remove java language version 23-preview: net.sourceforge.pmd.lang.java.JavaLanguageModule
  • update also java.md
  • update KotlinTestingDsl.kt
  • remove exclusions in pmd-core/src/main/resources/internal/all-java.xml
  • Update net.sourceforge.pmd.lang.java.LanguageVersionTest
  • Remove net.sourceforge.pmd.lang.java.ast.Java23PreviewTreeDumpTest (including resources)
  • Update net.sourceforge.pmd.lang.java.ast.AllJavaAstTreeDumpTest
  • Update net.sourceforge.pmd.dist.BinaryDistributionIT
• Update implementation for JEP 488: Primitive Types in Patterns, instanceof, and switch (Second Preview)
  • new preview: 507: Primitive Types in Patterns, instanceof, and switch (Third Preview)
  • "preview it for a third time, without change."
• Update implementation for JEP 492: Flexible Constructor Bodies (Third Preview)
  • finalized: 513: Flexible Constructor Bodies
  • "We here propose to finalize the feature in JDK 25, without change."
• Update implementation for JEP 494: Module Import Declarations (Second Preview)
  • finalized: 511: Module Import Declarations
  • "We here propose to finalize the feature in JDK 25, without change."
• Update implementation for JEP 495: Simple Source Files and Instance Main Methods (Fourth Preview)
  • finalized: 512: Compact Source Files and Instance Main Methods
  • "We here propose to finalize the feature in JDK 25, renaming simple source files to compact source files, with several minor improvements"
  • https://cr.openjdk.org/~gbierman/jep512/jep512-20250422/specs/compact-source-files-instance-main-methods-jls.html
• Write release notes
  • removed experimental: TODO
  • removed classes: TODO
  • deprecated classes: TODO
  • new experimental: TODO
• Make sure, we can build PMD with JDK25
  • ⚠ The kotlin-maven-plugin seems to be incompatible with java 25-ea
  • Maybe we need to upgrade it? See Bump kotlin.version from 1.9.24 to 2.2.0 #5864
  • Maybe setting language version / api version helps? see https://kotlinlang.org/docs/maven.html#attributes-specific-to-jvm
  • Turns out, we have to upgrade
    • see https://youtrack.jetbrains.com/issue/KT-73967/JDK-25-IllegalArgumentException-25-ea-with-EA-builds
    • Kotlin-Compiler was originally limited up to Java 24... see this fix JetBrains/kotlin@e0bf708
    • We need to upgrade to at least 2.1.20
• Add JDK25 to the build, so that we integration test with 25, if this is a LTS version
  • integration test in pmd-dist
  • Yes - Java 25 will be a LTS release
  • see [ci] Run integration test with Java 25 #5873
• Update https://github.com/pmd/java-regression-tests
  • new regular language features, so update needed
  • Note: This can only be done, after this issue has been implemented
  • see [java] Update java regression tests with Java 25 language features #5874
• Create a new issue for the next Java version 26
  • https://jdk.java.net/26/
  • https://openjdk.org/projects/jdk/26/
  • [java] Support Java 26 #5871