diff --git a/src/main/java/de/ids_mannheim/korap/index/FieldDocument.java b/src/main/java/de/ids_mannheim/korap/index/FieldDocument.java
index 89e839a..e8730ed 100644
--- a/src/main/java/de/ids_mannheim/korap/index/FieldDocument.java
+++ b/src/main/java/de/ids_mannheim/korap/index/FieldDocument.java
@@ -79,7 +79,8 @@
 
 
     public void addInt (String key, String value) {
-        this.addInt(key, Integer.parseInt(value));
+		if (value != null)
+			this.addInt(key, Integer.parseInt(value));
     };
 
 
@@ -284,7 +285,9 @@
     @Override
     public KrillDate setPubDate (String pubDate) {
         KrillDate date = super.setPubDate(pubDate);
-        this.addInt("pubDate", date.toString());
+		if (date != null) {
+			this.addInt("pubDate", date.toString());
+		};
         return date;
     };
 
@@ -293,7 +296,9 @@
     @Override
     public KrillDate setCreationDate (String creationDate) {
         KrillDate date = super.setCreationDate(creationDate);
-        this.addInt("creationDate", date.toString());
+		if (date != null) {
+			this.addInt("creationDate", date.toString());
+		};
         return date;
     };
 
diff --git a/src/main/resources/log4j.properties b/src/main/resources/log4j.properties
index 2805e78..074fbae 100644
--- a/src/main/resources/log4j.properties
+++ b/src/main/resources/log4j.properties
@@ -1,4 +1,4 @@
-log4j.rootLogger = ERROR, stdout
+# log4j.rootLogger = ERROR, stdout
 
 # Queries:
 # log4j.logger.de.ids_mannheim.korap.query.SpanNextQuery = TRACE, stdout
@@ -32,6 +32,7 @@
 # log4j.logger.de.ids_mannheim.korap.response.Match = TRACE, stdout
 
 # Index:
+log4j.logger.de.ids_mannheim.korap.index.Indexer = INFO, stdout
 # log4j.logger.de.ids_mannheim.korap.KrillIndex = TRACE, stdout
 # log4j.logger.de.ids_mannheim.korap.index.PositionsToOffset = TRACE, stdout
 # log4j.logger.de.ids_mannheim.korap.index.MultiTermTokenStream = TRACE, stdout