[SYNCOPE-1545] Fix generic config parameter values handling
diff --git a/wa/bootstrap/src/main/java/org/apache/syncope/wa/bootstrap/SyncopeWAPropertySourceLocator.java b/wa/bootstrap/src/main/java/org/apache/syncope/wa/bootstrap/SyncopeWAPropertySourceLocator.java
index 059af19..c76e29f 100644
--- a/wa/bootstrap/src/main/java/org/apache/syncope/wa/bootstrap/SyncopeWAPropertySourceLocator.java
+++ b/wa/bootstrap/src/main/java/org/apache/syncope/wa/bootstrap/SyncopeWAPropertySourceLocator.java
@@ -500,8 +500,8 @@
             }
         });
 
-        syncopeClient.getService(WAConfigService.class).list().
-                forEach(attr -> properties.put(attr.getSchema(), attr.getValues()));
+        syncopeClient.getService(WAConfigService.class).list().forEach(attr -> properties.put(
+                attr.getSchema(), attr.getValues().stream().collect(Collectors.joining(","))));
         LOG.debug("Collected WA properties: {}", properties);
         return new MapPropertySource(getClass().getName(), properties);
     }