More precise handling of the XStream errors

core/src/main/java/cucumber/runtime/table/TableConverter.java

@@ -107,8 +107,14 @@ private <T> List<T> toListOfComplexType(DataTable dataTable, Class<T> itemType)
             return Collections.unmodifiableList((List<T>) xStream.unmarshal(reader));
         } catch (AbstractReflectionConverter.UnknownFieldException e) {
             throw new CucumberException(e.getShortMessage());
+        } catch (AbstractReflectionConverter.DuplicateFieldException e) {
+            throw new CucumberException(e.getShortMessage());
         } catch (ConversionException e) {
-            throw new CucumberException(String.format("Can't assign null value to one of the primitive fields in %s. Please use boxed types.", e.get("class")));
+            if (e.getCause() instanceof NullPointerException) {
+                throw new CucumberException(String.format("Can't assign null value to one of the primitive fields in %s. Please use boxed types.", e.get("class")));
+            } else {
+                throw new CucumberException(e);
+            }
         }
     }
 

core/src/test/java/cucumber/runtime/table/ToDataTableTest.java

@@ -81,6 +81,20 @@ public void gives_a_nice_error_message_when_primitive_field_is_null() {
         }
     }
 
+    @Test
+    public void gives_a_meaningfull_error_message_when_field_is_repeated() {
+        try {
+            tc.toList(UserPojo.class, TableParser.parse("" +
+                    "| credits     | credits     |\n" +
+                    "| 5           | 5           |\n" +
+                    "", PARAMETER_INFO)
+            );
+            fail();
+        } catch (CucumberException e) {
+            assertEquals("Duplicate field credits", e.getMessage());
+        }
+    }
+
     @Test
     public void converts_list_of_beans_to_table_with_explicit_columns() {
         List<UserPojo> users = tc.toList(UserPojo.class, personTable());