diff --git a/okhttp/src/main/java/io/grpc/okhttp/OkHttpReadableBuffer.java b/okhttp/src/main/java/io/grpc/okhttp/OkHttpReadableBuffer.java
index 136ee8954a2..ebdbfa8b5cb 100644
--- a/okhttp/src/main/java/io/grpc/okhttp/OkHttpReadableBuffer.java
+++ b/okhttp/src/main/java/io/grpc/okhttp/OkHttpReadableBuffer.java
@@ -73,8 +73,11 @@ public void readBytes(byte[] dest, int destOffset, int length) {
 
   @Override
   public void readBytes(ByteBuffer dest) {
-    // We are not using it.
-    throw new UnsupportedOperationException();
+    try {
+      buffer.read(dest);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
   }
 
   @Override
diff --git a/okhttp/src/test/java/io/grpc/okhttp/OkHttpReadableBufferTest.java b/okhttp/src/test/java/io/grpc/okhttp/OkHttpReadableBufferTest.java
index 4aeeae2fa8b..8f6cc71e20a 100644
--- a/okhttp/src/test/java/io/grpc/okhttp/OkHttpReadableBufferTest.java
+++ b/okhttp/src/test/java/io/grpc/okhttp/OkHttpReadableBufferTest.java
@@ -44,12 +44,6 @@ public void setup() {
     }
   }
 
-  @Override
-  @Test
-  public void readToByteBufferShouldSucceed() {
-    // Not supported.
-  }
-
   @Override
   @Test
   public void partialReadToByteBufferShouldSucceed() {