Java 26 will be released in March 2026.

OpenJDK 26 GA is scheduled for 2026/03/17.

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

• JEP 530: Primitive Types in Patterns, instanceof, and switch (Fourth Preview)

In summary: https://javaalmanac.io/jdk/26/

This issue is similar to the previous: #5478

EA Release of JDK26 is available here: https://jdk.java.net/26/

Tasks:

• Add new java language versions 26 and 26-preview: net.sourceforge.pmd.lang.java.JavaLanguageModule
  • 26 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 9.9.1 ??:
  • 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
  • See chore(deps): bump org.ow2.asm:asm from 9.8 to 9.9 #6141
  • See chore(deps): bump org.ow2.asm:asm from 9.9 to 9.9.1 #6353
• Remove java language version 24-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.Java24PreviewTreeDumpTest (including resources)
  • Update net.sourceforge.pmd.lang.java.ast.AllJavaAstTreeDumpTest
  • Update net.sourceforge.pmd.dist.BinaryDistributionIT
• Update implementation for JEP 507: Primitive Types in Patterns, instanceof, and switch (Third Preview)
  • new: JEP 530: Primitive Types in Patterns, instanceof, and switch (Fourth Preview)
  • no change in syntax, but slight semantic change:

    We here propose to preview it for a fourth time with two changes: Enhance the
    definition of unconditional exactness,
    and apply tighter dominance
    checks in switch constructs. These changes enable the compiler to identify a wider
    range of coding errors, although a small number of switch constructs that were
    previously legal will now be rejected.

  • https://cr.openjdk.org/~abimpoudis/instanceof/jep530-20251112/specs/primitive-types-in-patterns-instanceof-switch-jls.html
• Move standardized Preview Language Features to Regular Features, if possible
  • see net.sourceforge.pmd.lang.java.ast.internal.LanguageLevelChecker
  • since 24 preview is now gone...
• Write release notes
  • removed experimental: no changes
  • removed classes: no changes
  • deprecated classes: no changes
  • new experimental: no changes
• Make sure, we can build PMD with JDK26
• Add JDK26 to the build, so that we integration test with 26, if this is a LTS version
  • integration test in pmd-dist
  • Yes - Java 26 will be a LTS release
  • TODO: create issue to update integration test after Java 26 is released
  • No - Java 26 will not be LTS release
• Update https://github.com/pmd/java-regression-tests
  • Yes, there are new regular language features, so update needed
  • Or No, there are now regular language features, no update needed
  • Note: This can only be done, after this issue has been implemented
  • TODO: create issue to update regression tests after PMD + Java 26 is released, if necessary
• Create a new issue for the next Java version 27
  • https://jdk.java.net/27/
  • https://openjdk.org/projects/jdk/27/
  • Done, see [java] Support Java 27 #6374
• Consider to create already now a version 27 (that is not the default)
  in order to avoid problems like Disable JDK 26-ea tests apache/commons-compress#724
  • we know, that Java 27 will be around in any case
  • that would allow downstream projects to test against the latest versions even with PMD
  • we would not add syntax/grammer/parser support for new language constructs yet (which are anyway not known yet)
  • on the other hand, the problem seems to be just an outdated asm library:

    java.lang.IllegalArgumentException: Unsupported class file major version 70
      at org.objectweb.asm.ClassReader.<init> (ClassReader.java:200)
    

  • Conclusion: Won't do this. For commons-compress, it uses pmd targetJdk 1.8. The only reason, why the build failed with java 26-ea was indeed the outdated asm library, which will be updated by dependabot in a timely manner anyway.
    • see https://github.com/apache/commons-compress/blob/b71186299118dacc442d7298b7c8c19fb7f95823/pom.xml#L38
    • and https://github.com/apache/commons-compress/blob/b71186299118dacc442d7298b7c8c19fb7f95823/pom.xml#L363