Ignore the signature-polymorphic MethodHandle in Animal Sniffer

[ppkarwasz]

MethodHandle's invokers (invokeExact, invoke) are signature-polymorphic: javac records the ad-hoc call-site descriptor in the bytecode, which no signature database lists, so the Animal Sniffer check on JDK 8 flags every such call site as an undefined reference — even though the invokers exist on all supported targets (Java 7+).

Seen in practice on apache/commons-xml#57, where six invokeExact call sites fail the JDK 8 CI legs; the workaround there is the same <ignore>java.lang.invoke.MethodHandle</ignore> in the component's own pom, which this change makes unnecessary for all components.

Only java.lang.invoke.MethodHandle is ignored: VarHandle is deliberately not listed, since it does not exist on a Java 8 target and a reference to it would be a real incompatibility.

🤖 Generated with Claude Code

[garydgregory]

@ppkarwasz
Are you sure? When I run locally on macOS, I see:

[INFO] --- animal-sniffer:1.27:check (checkAPIcompatibility) @ commons-xml ---
[INFO] Checking unresolved references to org.codehaus.mojo.signature:java18:1.0
[INFO] 

Using:

Apache Maven 3.9.16 (2bdd9fddda4b155ebf8000e807eb73fd829a51d5)
Maven home: /opt/homebrew/Cellar/maven/3.9.16/libexec
Java version: 1.8.0_481, vendor: Oracle Corporation, runtime: /Library/Java/JavaVirtualMachines/jdk-1.8.jdk/Contents/Home/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "26.6.2", arch: "aarch64", family: "mac"

On GH CI here on Windows and Java 8, I see the same as above, using:

Apache Maven 3.9.16 (2bdd9fddda4b155ebf8000e807eb73fd829a51d5)
Maven home: C:\ProgramData\chocolatey\lib\maven\apache-maven-3.9.16
Java version: 1.8.0_502, vendor: Temurin, runtime: C:\hostedtoolcache\windows\Java_Temurin-Hotspot_jdk\8.0.502-7\x64\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows server 2025", version: "10.0", arch: "amd64", family: "windows"

What do you see and where?

[garydgregory]

Oh, I see, you disabled it... ok.