Log a warning when more than one IoC dependency is found in the classpath

core/src/main/java/cucumber/runtime/NoInstancesException.java

@@ -0,0 +1,12 @@
+package cucumber.runtime;
+
+public class NoInstancesException extends CucumberException {
+
+    public NoInstancesException(Class parentType) {
+        super(createMessage(parentType));
+    }
+
+    private static String createMessage(Class parentType) {
+        return String.format("Couldn't find a single implementation of " + parentType);
+    }
+}

core/src/main/java/cucumber/runtime/Reflections.java

@@ -16,9 +16,9 @@ public <T> T instantiateExactlyOneSubclass(Class<T> parentType, String packageNa
         if (instances.size() == 1) {
             return instances.iterator().next();
         } else if (instances.size() == 0) {
-            throw new CucumberException("Couldn't find a single implementation of " + parentType);
+            throw new NoInstancesException(parentType);
         } else {
-            throw new CucumberException("Expected only one instance, but found too many: " + instances);
+            throw new TooManyInstancesException(instances);
         }
     }
 

core/src/main/java/cucumber/runtime/TooManyInstancesException.java

@@ -0,0 +1,14 @@
+package cucumber.runtime;
+
+import java.util.Collection;
+
+public class TooManyInstancesException extends CucumberException {
+
+    public TooManyInstancesException(Collection instances) {
+        super(createMessage(instances));
+    }
+
+    private static String createMessage(Collection instances) {
+        return String.format("Expected only one instance, but found too many: " + instances);
+    }
+}

java/src/main/java/cucumber/runtime/java/JavaBackend.java

@@ -2,14 +2,7 @@
 
 import cucumber.api.java.After;
 import cucumber.api.java.Before;
-import cucumber.runtime.Backend;
-import cucumber.runtime.ClassFinder;
-import cucumber.runtime.CucumberException;
-import cucumber.runtime.DuplicateStepDefinitionException;
-import cucumber.runtime.Glue;
-import cucumber.runtime.Reflections;
-import cucumber.runtime.UnreportedStepExecutor;
-import cucumber.runtime.Utils;
+import cucumber.runtime.*;
 import cucumber.runtime.io.MultiLoader;
 import cucumber.runtime.io.ResourceLoader;
 import cucumber.runtime.io.ResourceLoaderClassFinder;
@@ -61,7 +54,10 @@ public static ObjectFactory loadObjectFactory(ClassFinder classFinder) {
         try {
             Reflections reflections = new Reflections(classFinder);
             objectFactory = reflections.instantiateExactlyOneSubclass(ObjectFactory.class, "cucumber.runtime", new Class[0], new Object[0]);
-        } catch (CucumberException ce) {
+        } catch (TooManyInstancesException e) {
+            System.out.println(getMultipleObjectFactoryLogMessage());
+            objectFactory = new DefaultJavaObjectFactory();
+        } catch (NoInstancesException e) {
             objectFactory = new DefaultJavaObjectFactory();
         }
         return objectFactory;
@@ -141,4 +137,14 @@ void addHook(Annotation annotation, Method method) {
             glue.addAfterHook(new JavaHookDefinition(method, tagExpressions, ((After) annotation).order(), timeout, objectFactory));
         }
     }
+
+    private static String getMultipleObjectFactoryLogMessage() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("More than one Cucumber ObjectFactory was found in the classpath\n\n");
+        sb.append("You probably may have included, for instance, cucumber-spring AND cucumber-guice as part of\n");
+        sb.append("your dependencies. When this happens, Cucumber falls back to instantiating the\n");
+        sb.append("DefaultJavaObjectFactory implementation which doesn't provide IoC.\n");
+        sb.append("In order to enjoy IoC features, please remove the unnecessary dependencies from your classpath.\n");
+        return sb.toString();
+    }
 }