Better error message on missing field

2 files changed, 4 insertions, 2 deletions

diff --git a/document/src/main/java/com/yahoo/document/DocumentType.java b/document/src/main/java/com/yahoo/document/DocumentType.java
index a616c853bf4..f3ff6e4ed30 100755
--- a/document/src/main/java/com/yahoo/document/DocumentType.java
+++ b/document/src/main/java/com/yahoo/document/DocumentType.java
@@ -328,8 +328,8 @@ public class DocumentType extends StructuredDataType {
     /**
      * Gets the field matching a given name.
      *
-     * @param name The name of a field.
-     * @return Returns the matching field, or null if not found.
+     * @param name the name of a field.
+     * @return returns the matching field, or null if not found.
      */
     public Field getField(String name) {
         Field field = headerType.getField(name);
diff --git a/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java b/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java
index 7e32a6b8b44..3ab9f72504b 100644
--- a/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java
+++ b/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java
@@ -117,6 +117,8 @@ public class VespaJsonDocumentReader {
 
     private void addFieldUpdates(DocumentUpdate update, TokenBuffer buffer, String fieldName) {
         Field field = update.getType().getField(fieldName);
+        if (field == null)
+            throw new IllegalArgumentException("No field named '" + fieldName + "' in " + update.getType());
         int localNesting = buffer.nesting();
         FieldUpdate fieldUpdate = FieldUpdate.create(field);