diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexInput.java b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexInput.java
index 33457e4243a..4f15ce61c0d 100644
--- a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexInput.java
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexInput.java
@@ -46,7 +46,7 @@ public abstract class FixedIntBlockIndexInput extends IntIndexInput {
   }
 
   @Override
-  public Reader reader() throws IOException {
+  public IntIndexInput.Reader reader() throws IOException {
     final int[] buffer = new int[blockSize];
     final IndexInput clone = in.clone();
     // TODO: can this be simplified?
@@ -59,7 +59,7 @@ public abstract class FixedIntBlockIndexInput extends IntIndexInput {
   }
 
   @Override
-  public Index index() {
+  public IntIndexInput.Index index() {
     return new Index();
   }
 
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexOutput.java b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexOutput.java
index 004e51c49ab..ec89356f788 100644
--- a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexOutput.java
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/FixedIntBlockIndexOutput.java
@@ -51,7 +51,7 @@ public abstract class FixedIntBlockIndexOutput extends IntIndexOutput {
   protected abstract void flushBlock() throws IOException;
 
   @Override
-  public Index index() throws IOException {
+  public IntIndexOutput.Index index() throws IOException {
     return new Index();
   }
 
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexInput.java b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexInput.java
index 9505c1e253c..0e4d2983a94 100644
--- a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexInput.java
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexInput.java
@@ -48,7 +48,7 @@ public abstract class VariableIntBlockIndexInput extends IntIndexInput {
   }
 
   @Override
-  public Reader reader() throws IOException {
+  public IntIndexInput.Reader reader() throws IOException {
     final int[] buffer = new int[maxBlockSize];
     final IndexInput clone = in.clone();
     // TODO: can this be simplified?
@@ -61,7 +61,7 @@ public abstract class VariableIntBlockIndexInput extends IntIndexInput {
   }
 
   @Override
-  public Index index() {
+  public IntIndexInput.Index index() {
     return new Index();
   }
 
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexOutput.java b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexOutput.java
index 9d31c3c824e..c035e231685 100644
--- a/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexOutput.java
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/intblock/VariableIntBlockIndexOutput.java
@@ -60,7 +60,7 @@ public abstract class VariableIntBlockIndexOutput extends IntIndexOutput {
   protected abstract int add(int value) throws IOException;
 
   @Override
-  public Index index() throws IOException {
+  public IntIndexOutput.Index index() throws IOException {
     return new Index();
   }