diff --git a/contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/ClobTransformer.java b/contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/ClobTransformer.java
index 54c11a9444e..e28c7a2eb20 100644
--- a/contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/ClobTransformer.java
+++ b/contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/ClobTransformer.java
@@ -71,7 +71,7 @@ public class ClobTransformer extends Transformer {
     char[] buf = new char[1024];
     int len;
     try {
-      while ((len = reader.read(buf)) != 0) {
+      while ((len = reader.read(buf)) != -1) {
         sb.append(buf, 0, len);
       }
     } catch (IOException e) {