diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SampleTypePE.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SampleTypePE.java
index 1d06c76bf82f4549ba8cc994f43c4d375eb1129f..08245e1c842c3fa4e84efb5c008f5ce0cf520ea0 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SampleTypePE.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SampleTypePE.java
@@ -62,15 +62,15 @@ public final class SampleTypePE extends EntityTypePE
     // NOTE: Should be objects in order to allow Hibernate to find SampleType by example.
     //
 
-    private Boolean listable = true;
+    private Boolean listable;
 
-    private Integer generatedFromHierarchyDepth = 0;
+    private Integer generatedFromHierarchyDepth;
 
-    private Integer containerHierarchyDepth = 0;
+    private Integer containerHierarchyDepth;
 
-    private Boolean subcodeUnique = false;
+    private Boolean subcodeUnique;
 
-    private Boolean autoGeneratedCode = false;
+    private Boolean autoGeneratedCode;
 
     private String generatedCodePrefix;
 
diff --git a/screening/sourceTest/java/ch/systemsx/cisd/openbis/plugin/screening/server/logic/ScreeningApiImplTest.java b/screening/sourceTest/java/ch/systemsx/cisd/openbis/plugin/screening/server/logic/ScreeningApiImplTest.java
index 04d32cd52adb6f48f7dd3efbd36f00d67efa069e..e472a198e6fa17a8da5376b60e62beb569046654 100644
--- a/screening/sourceTest/java/ch/systemsx/cisd/openbis/plugin/screening/server/logic/ScreeningApiImplTest.java
+++ b/screening/sourceTest/java/ch/systemsx/cisd/openbis/plugin/screening/server/logic/ScreeningApiImplTest.java
@@ -403,7 +403,13 @@ public class ScreeningApiImplTest extends AbstractServerTestCase
     {
         SamplePE sample = new SamplePE();
         sample.setId(1L);
-        sample.setSampleType(new SampleTypePE());
+        final SampleTypePE sampleType = new SampleTypePE();
+        sampleType.setContainerHierarchyDepth(1);
+        sampleType.setGeneratedFromHierarchyDepth(1);
+        sampleType.setListable(false);
+        sampleType.setAutoGeneratedCode(false);
+        sampleType.setSubcodeUnique(false);
+        sample.setSampleType(sampleType);
         return sample;
     }