diff --git a/image_readers/source/java/ch/systemsx/cisd/imagereaders/ImageReaderFactory.java b/image_readers/source/java/ch/systemsx/cisd/imagereaders/ImageReaderFactory.java
index aad31f3ac4c8fc43a15fb6d9a585e3aa6059873f..a9059274b56788b14bb592588b7bf74bdbe7031f 100644
--- a/image_readers/source/java/ch/systemsx/cisd/imagereaders/ImageReaderFactory.java
+++ b/image_readers/source/java/ch/systemsx/cisd/imagereaders/ImageReaderFactory.java
@@ -123,7 +123,7 @@ public class ImageReaderFactory
                 return library;
             }
         }
-        throw new IllegalArgumentException("Unvalid library name '" + libraryName + "'");
+        return null;
     }
 
     /**
diff --git a/image_readers/sourceTest/java/ch/systemsx/cisd/imagereaders/ImageReaderFactoryTest.java b/image_readers/sourceTest/java/ch/systemsx/cisd/imagereaders/ImageReaderFactoryTest.java
index 02cea552d367824d05c2fa9b277918fa9c998b54..139516f6dc3effc24443fb8eb273f4eafed9fdd8 100644
--- a/image_readers/sourceTest/java/ch/systemsx/cisd/imagereaders/ImageReaderFactoryTest.java
+++ b/image_readers/sourceTest/java/ch/systemsx/cisd/imagereaders/ImageReaderFactoryTest.java
@@ -83,10 +83,10 @@ public class ImageReaderFactoryTest extends AbstractImageReaderFactoryTest
 
     }
 
-    @Test(expectedExceptions = IllegalArgumentException.class)
-    public void testGetInvalidLibrary()
+    public void testGetReaderFromInvalidLibrary()
     {
-        ImageReaderFactory.tryGetReaderForFile("invalid_library", null);
+        IImageReader reader = ImageReaderFactory.tryGetReaderForFile("invalid_library", null);
+        assertNull(reader);
     }
 
     @Test(expectedExceptions = IOExceptionUnchecked.class)