[Java] Fix duplicate step defintion when using interfaces (#2759)

Co-authored-by: Julien Kronegg <julien [at] kronegg.ch>
Co-authored-by: M.P. Korstanje <[email protected]>

Author: jkronegg

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - [Core] Fixed `cucumber.publish.enabled=false` ([#2747](https://github.com/cucumber/cucumber-jvm/pull/2747) M.P. Korstanje)
 - [JUnit Platform Engine] Fixed `cucumber.publish.enabled=false` ([#2747](https://github.com/cucumber/cucumber-jvm/pull/2747) M.P. Korstanje)
+- [Java] Fixed duplicate step definition for classes with interfaces ([#2757](https://github.com/cucumber/cucumber-jvm/issues/2757) Julien Kronegg) 
 
 ## [7.12.0] - 2023-04-29
 ### Added

cucumber-java/src/main/java/io/cucumber/java/MethodScanner.java

@@ -55,6 +55,17 @@ private static void scan(BiConsumer<Method, Annotation> consumer, Class<?> aClas
         if (Object.class.equals(method.getDeclaringClass())) {
             return;
         }
+
+        // exclude bridge methods: when a class implements a method
+        // from the interface but specializes the return type, two methods will
+        // be generated. One with the return type of the interface and one
+        // with the specialized return type. The former is a bridge method.
+        // Depending on the JVM, the method annotations are also applied to
+        // the bridge method.
+        if (method.isBridge()) {
+            return;
+        }
+
         scan(consumer, aClass, method, method.getAnnotations());
     }
 

cucumber-java/src/test/java/io/cucumber/java/JavaBackendTest.java

@@ -14,7 +14,6 @@
 import org.mockito.junit.jupiter.MockitoExtension;
 
 import java.net.URI;
-import java.util.Arrays;
 import java.util.List;
 
 import static java.lang.Thread.currentThread;

cucumber-java/src/test/java/io/cucumber/java/MethodScannerTest.java

@@ -1,5 +1,6 @@
 package io.cucumber.java;
 
+import io.cucumber.java.en.Given;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -41,6 +42,13 @@ void scan_ignores_object() {
         assertThat(scanResult, empty());
     }
 
+    @Test
+    void scan_ignores_bridge_methods() throws NoSuchMethodException {
+        Method method = SpecializedReturnType.class.getMethod("test");
+        MethodScanner.scan(SpecializedReturnType.class, backend);
+        assertThat(scanResult, contains(new SimpleEntry<>(method, method.getAnnotations()[0])));
+    }
+
     @Test
     void scan_ignores_non_instantiable_class() {
         MethodScanner.scan(NonStaticInnerClass.class, backend);
@@ -81,4 +89,17 @@ public void m() {
 
     }
 
+    public interface GenericReturnType {
+        Number test();
+
+    }
+
+    public static class SpecializedReturnType implements GenericReturnType {
+
+        @Given("test")
+        public Integer test() {
+            return 1;
+        }
+
+    }
 }