Fix comment (#11299)

src/main/java/org/jabref/model/entry/BibEntry.java

@@ -45,6 +45,7 @@
 import org.jabref.model.strings.StringUtil;
 import org.jabref.model.util.MultiKeyMap;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.eventbus.EventBus;
 import com.tobiasdiez.easybind.EasyBind;
 import com.tobiasdiez.easybind.optional.OptionalBinding;
@@ -353,19 +354,22 @@ private Optional<String> genericGetResolvedFieldOrAlias(Field field, BibDatabase
     }
 
     /**
-     * Returns this entry's ID.
+     * Returns this entry's ID. It is used internally to distinguish different BibTeX entries.
+     * <p>
+     * It is <emph>not</emph> the citation key (which is stored in the {@link InternalField#KEY_FIELD} and also known as BibTeX key).
      */
     public String getId() {
         return id;
     }
 
     /**
-     * Sets this entry's identifier (ID). It is used internally  to distinguish different BibTeX entries. It is <emph>not</emph> the citation key. The BibTexKey is the {@link InternalField#KEY_FIELD}.
+     * Sets this entry's identifier (ID).
      * <p>
      * The entry is also updated in the shared database - provided the database containing it doesn't veto the change.
      *
      * @param id The ID to be used
      */
+    @VisibleForTesting
     public void setId(String id) {
         Objects.requireNonNull(id, "Every BibEntry must have an ID");