diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java b/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java
index d58a8f9bc4..ec578fd6d3 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java
@@ -30,8 +30,9 @@ import org.springframework.core.convert.converter.ConditionalGenericConverter;
  * any type that the {@link ConversionService} support via {@code byte[]}.
  *
  * @author Phillip Webb
+ * @since 4.0
  */
-public class ByteBufferConverter implements ConditionalGenericConverter {
+final class ByteBufferConverter implements ConditionalGenericConverter {
 
 	private static final TypeDescriptor BYTE_BUFFER_TYPE = TypeDescriptor.valueOf(ByteBuffer.class);
 
diff --git a/spring-websocket/src/test/java/org/springframework/web/socket/adapter/ConvertingEncoderDecoderSupportTests.java b/spring-websocket/src/test/java/org/springframework/web/socket/adapter/ConvertingEncoderDecoderSupportTests.java
index 1ed49a81e7..ff2bb7486d 100644
--- a/spring-websocket/src/test/java/org/springframework/web/socket/adapter/ConvertingEncoderDecoderSupportTests.java
+++ b/spring-websocket/src/test/java/org/springframework/web/socket/adapter/ConvertingEncoderDecoderSupportTests.java
@@ -17,7 +17,6 @@
 package org.springframework.web.socket.adapter;
 
 import java.nio.ByteBuffer;
-
 import javax.websocket.DecodeException;
 import javax.websocket.Decoder;
 import javax.websocket.EncodeException;
@@ -28,13 +27,14 @@ import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
+
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.converter.Converter;
-import org.springframework.core.convert.support.ByteBufferConverter;
+import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.core.convert.support.GenericConversionService;
 import org.springframework.web.context.WebApplicationContext;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
@@ -188,8 +188,7 @@ public class ConvertingEncoderDecoderSupportTests {
 
 		@Bean
 		public ConversionService webSocketConversionService() {
-			GenericConversionService conversionService = new GenericConversionService();
-			conversionService.addConverter(new ByteBufferConverter(conversionService));
+			GenericConversionService conversionService = new DefaultConversionService();
 			conversionService.addConverter(new MyTypeToStringConverter());
 			conversionService.addConverter(new MyTypeToBytesConverter());
 			conversionService.addConverter(new StringToMyTypeConverter());