AspectJ 1.9.19

Please note that Bugzilla for issue management is deprecated and new issues should be filed as GitHub issues. The list of issues addressed for 1.9.19 can be found here:

• GitHub 1.9.19
• Bugzilla 1.9.19

New features

AspectJ 1.9.19 supports Java 19 and its final, preview and incubator features, such as:

• Record patterns (preview)
• Virtual threads (preview)
• Pattern matching for switch (preview 3)
• Structured concurrency (incubator)

Please note that the upstream Eclipse Java Compiler (ECJ) which the AspectJ Compiler (AJC) is a fork of still has some open issues concerning Java 19 preview feature support, see the list in this comment. AJC therefore inherits the same problems for the specific cases described in the linked issues.

Improvements

• Improve condy (constant dynamic) support. Together with some custom compilation or weaving options, this helps to avoid a problem when using JaCoCo together with AspectJ, see this comment in #170 for more details.

Code examples

You can find some sample code in the AspectJ test suite under the respective AspectJ version in which the features were first supported (possibly as JVM preview features):

• Pattern matching for switch (preview 1)
• Pattern matching for switch (preview 2)
• Pattern matching for switch (preview 3), record patterns (preview 1)
• Please note that presently there is no specific sample code for virtual threads and structured concurrency in the AspectJ code base, because these are just new APIs, no Java language features. You can find sample code for these concurrency features elsewhere, e.g. in the corresponding JEPs. In AspectJ, they should just work transparently like any other Java API.

Other changes and bug fixes

• Fix (or rather work around) an old bug occurring when compiling or weaving code using ITD to declare annotations with SOURCE retention on types, methods, constructors or fields. While declaring such annotations does not make sense to begin with, at least the AspectJ weaver or compiler should handle the situation gracefully, which now it does by simply ignoring errors caused by it. See Bugzilla #366085 and pull request #196. Better than this workaround would be for the compiler or weaver to actually print a warning when meeting source level annotations in declare statements. Hence, follow-up issue #201 was created.
• Remove legacy AspectJ Browser code and documentation.
• Thanks to Andrey Turbanov for several clean code contributions.

AspectJ usage hints

AspectJ compiler build system requirements

Since 1.9.7, the AspectJ compiler ajc (contained in the aspectjtools library) no longer works on JDKs 8 to 10. The minimum compile-time requirement is now JDK 11 due to upstream changes in the Eclipse Java Compiler (subset of JDT Core), which AspectJ is a fork of. You can still compile to legacy target versions as low as Java 1.3 when compiling plain Java code or using plain Java ITD constructs which do not require the AspectJ runtime aspectjrt, but the compiler itself needs JDK 11+. Just like in previous AspectJ versions, both the runtime aspectjrt and the load-time weaver aspectjweaver still only require JRE 8+.

Use LTW on Java 16+

Please note that if you want to use load-time weaving on Java 16+, the weaving agent collides with JEP 396 (Strongly Encapsulate JDK Internals by Default) and related subsequent JEPs. Therefore, you need to set the JVM parameter --add-opens java.base/java.lang=ALL-UNNAMED in order to enable aspect weaving. This is due to the fact that the weaver uses internal APIs for which we have not found an adequate replacement yet when defining classes in different classloaders.

Compile with Java preview features

For features marked as preview on a given JDK, you need to compile with ajc --enable-preview and run with java --enable-preview on that JDK.

Please note that you cannot run code compiled with preview features on any other JDK than the one used for compilation. For example, records compiled with preview on JDK 15 cannot be used on JDK 16 without recompilation. This is a JVM limitation unrelated to AspectJ. Also, e.g. sealed classes are preview-1 on JDK 15 and preview-2 on JDK 16. You still need to recompile, no matter what.

Available: 1.9.19 on 21-Dec-2022