diff --git a/src/main/java/net/sf/jabref/model/entry/BibtexEntry.java b/src/main/java/net/sf/jabref/model/entry/BibtexEntry.java
index 6636b2b6025..10728152fb0 100644
--- a/src/main/java/net/sf/jabref/model/entry/BibtexEntry.java
+++ b/src/main/java/net/sf/jabref/model/entry/BibtexEntry.java
@@ -494,13 +494,7 @@ public void putKeywords(ArrayList<String> keywords) {
         String oldValue = this.getField("keywords");
         String newValue;
         if (!keywords.isEmpty()) {
-            StringBuilder sb = new StringBuilder();
-            for (String keyword : keywords) {
-                sb.append(keyword);
-                sb.append(", ");
-            }
-            sb.delete(sb.length() - 2, sb.length());
-            newValue = sb.toString();
+            newValue = String.join(", ", keywords);
         } else {
             newValue = null;
         }
diff --git a/src/main/java/net/sf/jabref/model/entry/EntryUtil.java b/src/main/java/net/sf/jabref/model/entry/EntryUtil.java
index 9483e368b15..40c9e2beb7a 100644
--- a/src/main/java/net/sf/jabref/model/entry/EntryUtil.java
+++ b/src/main/java/net/sf/jabref/model/entry/EntryUtil.java
@@ -62,24 +62,6 @@ public static List<String> getRemainder(List<String> all, List<String> subset) {
         return al;
     }
 
-    /**
-	 * Concatenate two String arrays
-	 *
-	 * @param array1
-	 *            the first string array
-	 * @param array2
-	 *            the second string array
-	 * @return The concatenation of array1 and array2
-	 */
-	public static String[] arrayConcat(String[] array1, String[] array2) {
-		int len1 = array1.length;
-		int len2 = array2.length;
-		String[] union = new String[len1 + len2];
-		System.arraycopy(array1, 0, union, 0, len1);
-		System.arraycopy(array2, 0, union, len1, len2);
-		return union;
-	}
-
     /**
      * @param keywords a String of keywords
      * @return an ArrayList containing the keywords. An emtpy list if keywords are null or empty
diff --git a/src/test/java/net/sf/jabref/model/entry/BibtexEntryTests.java b/src/test/java/net/sf/jabref/model/entry/BibtexEntryTests.java
index a6ad6fc069a..2287ce570ab 100644
--- a/src/test/java/net/sf/jabref/model/entry/BibtexEntryTests.java
+++ b/src/test/java/net/sf/jabref/model/entry/BibtexEntryTests.java
@@ -122,7 +122,41 @@ public void testKeywordMethods() {
         Assert.assertArrayEquals(expected2, be.getSeparatedKeywords().toArray());
 
         BibtexEntry be2 = new BibtexEntry();
+        Assert.assertTrue(be2.getSeparatedKeywords().isEmpty());
+        be2.addKeyword("");
+        Assert.assertTrue(be2.getSeparatedKeywords().isEmpty());
         be2.addKeywords(be.getSeparatedKeywords());
         Assert.assertArrayEquals(expected2, be2.getSeparatedKeywords().toArray());
     }
+
+    @Test
+    public void testGroupAndSearchHits() {
+        BibtexEntry be = new BibtexEntry();
+        be.setGroupHit(true);
+        Assert.assertTrue(be.isGroupHit());
+        be.setGroupHit(false);
+        Assert.assertFalse(be.isGroupHit());
+        be.setSearchHit(true);
+        Assert.assertTrue(be.isSearchHit());
+        be.setSearchHit(false);
+        Assert.assertFalse(be.isSearchHit());
+
+    }
+
+    @Test
+    public void testCiteKeyAndID() {
+        BibtexEntry be = new BibtexEntry();
+        Assert.assertFalse(be.hasCiteKey());
+        be.setField("author", "Albert Einstein");
+        be.setField(BibtexEntry.KEY_FIELD, "Einstein1931");
+        Assert.assertTrue(be.hasCiteKey());
+        Assert.assertEquals("Einstein1931", be.getCiteKey());
+        Assert.assertEquals("Albert Einstein", be.getField("author"));
+        be.clearField("author");
+        Assert.assertNull(be.getField("author"));
+
+        String id = IdGenerator.next();
+        be.setId(id);
+        Assert.assertEquals(id, be.getId());
+    }
 }