diff --git a/lucene/grouping/src/java/org/apache/lucene/search/grouping/GroupingSearch.java b/lucene/grouping/src/java/org/apache/lucene/search/grouping/GroupingSearch.java
index e2d0210f464..07162d91464 100644
--- a/lucene/grouping/src/java/org/apache/lucene/search/grouping/GroupingSearch.java
+++ b/lucene/grouping/src/java/org/apache/lucene/search/grouping/GroupingSearch.java
@@ -456,7 +456,7 @@ public class GroupingSearch {
    * This prevents growing data structures many times. This can improve the performance of the grouping at the cost of
    * more initial RAM.
    * <p/>
-   * The {@link #allGroups} and {@link #allGroupHeads} features use this option.
+   * The {@link #setAllGroups} and {@link #setAllGroupHeads} features use this option.
    * Defaults to 128.
    *
    * @param initialSize The initial size of some internal used data structures
diff --git a/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionAllGroupHeadsCollector.java b/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionAllGroupHeadsCollector.java
index 19a21544579..2f5b5425f5e 100644
--- a/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionAllGroupHeadsCollector.java
+++ b/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionAllGroupHeadsCollector.java
@@ -116,7 +116,10 @@ public class FunctionAllGroupHeadsCollector extends AbstractAllGroupHeadsCollect
     }
   }
 
-  class GroupHead extends AbstractAllGroupHeadsCollector.GroupHead<MutableValue> {
+  /** Holds current head document for a single group.
+   *
+   * @lucene.experimental */
+  public class GroupHead extends AbstractAllGroupHeadsCollector.GroupHead<MutableValue> {
 
     final FieldComparator<?>[] comparators;
 
diff --git a/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionDistinctValuesCollector.java b/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionDistinctValuesCollector.java
index d15a5f3f284..d7f91682441 100644
--- a/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionDistinctValuesCollector.java
+++ b/lucene/grouping/src/java/org/apache/lucene/search/grouping/function/FunctionDistinctValuesCollector.java
@@ -76,7 +76,10 @@ public class FunctionDistinctValuesCollector extends AbstractDistinctValuesColle
     countMval = countFiller.getValue();
   }
 
-  static class GroupCount extends AbstractDistinctValuesCollector.GroupCount<MutableValue> {
+  /** Holds distinct values for a single group.
+   *
+   * @lucene.experimental */
+  public static class GroupCount extends AbstractDistinctValuesCollector.GroupCount<MutableValue> {
 
     GroupCount(MutableValue groupValue) {
       super(groupValue);
diff --git a/lucene/grouping/src/java/org/apache/lucene/search/grouping/term/TermDistinctValuesCollector.java b/lucene/grouping/src/java/org/apache/lucene/search/grouping/term/TermDistinctValuesCollector.java
index 320093503ee..8d164796787 100644
--- a/lucene/grouping/src/java/org/apache/lucene/search/grouping/term/TermDistinctValuesCollector.java
+++ b/lucene/grouping/src/java/org/apache/lucene/search/grouping/term/TermDistinctValuesCollector.java
@@ -124,7 +124,10 @@ public class TermDistinctValuesCollector extends AbstractDistinctValuesCollector
     }
   }
 
-  static class GroupCount extends AbstractDistinctValuesCollector.GroupCount<BytesRef> {
+  /** Holds distinct values for a single group.
+   *
+   * @lucene.experimental */
+  public static class GroupCount extends AbstractDistinctValuesCollector.GroupCount<BytesRef> {
 
     int[] ords;