Add JPMS ServiceLoader Support with Multi-Release JAR #500
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**Note:** This is not a complete solution as handling of JDK 8 compatibility is outstanding. Currently, the fix would break usage of JDK 8. Enable `exec:java`-goal to execute Java applications using the Java Platform Module System (JPMS) with proper ServiceLoader support. Changes: - Split execution logic into classpath and module-path modes - Detect module syntax (module/class) in mainClass parameter - Create ModuleLayer with resolveAndBind() to include service providers - Use ModuleLayer.Controller to open packages for reflective access - Set thread context classloader to module's classloader The plugin now properly handles: - Module-path execution when `mainClass` uses "module/class" syntax - ServiceLoader provider discovery and binding in modular applications - Reflective access to main methods in unexported packages - Mixed module and classpath dependencies Integration test mexec-mojohausgh-426 validates the ServiceLoader functionality with a multi-module JPMS application (contract, provider, consumer). Technical implementation: - Use Configuration.resolveAndBind() instead of resolve() to include service providers declared with "uses" in module-info - Obtain ModuleLayer.Controller to programmatically open packages via addOpens() for reflective main method invocation - Load classes through the module layer's ClassLoader to maintain proper module isolation and visibility The fix was created in the course of support-and-care/maven-support-and-care#138.
This commit fixes two issues that caused build failures in GitHub: 1. JSR-512 Main Method Detection Problem: Tests failed with error: "The specified mainClass doesn't contain a main method with appropriate signature" JSR-512 (Java 21+) allows flexible main methods that can be non-public and instance methods. The original code used getMethod() which only finds PUBLIC methods, causing it to fail when searching for package-private main methods. Solution: - Changed from getMethod() to getDeclaredMethod() for JSR-512 - Added setAccessible(true) for non-public method invocation - Created findMethod() helper that searches class hierarchy - Validates return type is void (JSR-512 requirement) - Maintains correct priority order: 1. static void main(String[]) - traditional 2. static void main() - JSR-512 static no-args 3. void main(String[]) - JSR-512 instance with args 4. void main() - JSR-512 instance no-args 2. SystemExitException Logging Problem: Integration tests expected [ERROR] log prefix for SystemExitException but it was missing. When SystemExitException was thrown during method invocation, it got wrapped in InvocationTargetException and bypassed the logging code. Solution: - Added special handling in InvocationTargetException catch - Detects SystemExitException in the cause chain - Logs with appropriate level (ERROR for non-zero exit codes) - Re-throws the exception to maintain expected behavior
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Add full JPMS support (Java 9+) while maintaining Java 8 compatibility
by a Multi-Release JAR.
Configuration.resolveAndBind()for ServiceLoader withmodule/classNamesyntax supportby using
getDeclaredMethod()instead ofgetMethod()java9-mrjarauto-activates on JDK 9+ forversioned compilation