Incorporated misc. suggestions from the PR.

spring-web-reactive/src/main/java/org/springframework/core/io/buffer/DataBuffer.java

@@ -23,9 +23,6 @@ import java.nio.ByteBuffer;
 /**
  * Basic abstraction over byte buffers.
  *
- * <p>Mainly for internal use within the framework; consider Netty's
- * {@link io.netty.buffer.ByteBuf} for a more comprehensive byte buffer.
- *
  * @author Arjen Poutsma
  */
 public interface DataBuffer {

spring-web-reactive/src/main/java/org/springframework/core/io/buffer/DefaultDataBuffer.java

@@ -28,12 +28,9 @@ import org.springframework.util.ObjectUtils;
 
 /**
  * Default implementation of the {@link DataBuffer} interface that uses a {@link
- * ByteBuffer} internally, with separate read and write positions. Typically constructed
+ * ByteBuffer} internally, with separate read and write positions. Constructed
  * using the {@link DefaultDataBufferAllocator}.
  *
- * <p>This class is rather limited; consider using Netty's
- * {@link io.netty.buffer.ByteBuf} and {@link NettyDataBuffer} for a more comprehensive byte buffer.
-
  * @author Arjen Poutsma
  * @see DefaultDataBufferAllocator
  */

spring-web-reactive/src/main/java/org/springframework/core/io/buffer/DefaultDataBufferAllocator.java

@@ -21,9 +21,6 @@ import java.nio.ByteBuffer;
 /**
  * Default implementation of the {@code DataBufferAllocator} interface.
  *
- * <p>This class is rather limited; consider using Netty's
- * {@link io.netty.buffer.ByteBuf} and {@link NettyDataBuffer} for a more comprehensive
- * byte buffer.
  * @author Arjen Poutsma
  */
 public class DefaultDataBufferAllocator implements DataBufferAllocator {
@@ -70,7 +67,7 @@ public class DefaultDataBufferAllocator implements DataBufferAllocator {
 
 	@Override
 	public String toString() {
-		return "DefaultDataBufferFactory";
+		return "DefaultDataBufferFactory - preferDirect: " + this.preferDirect;
 	}
 
 }

spring-web-reactive/src/main/java/org/springframework/core/io/buffer/NettyDataBuffer.java

@@ -107,12 +107,9 @@ public class NettyDataBuffer implements DataBuffer {
 	public NettyDataBuffer write(DataBuffer... buffers) {
 		if (!ObjectUtils.isEmpty(buffers)) {
 			if (buffers[0] instanceof NettyDataBuffer) {
-				NettyDataBuffer[] copy =
-						Arrays.copyOf(buffers, buffers.length, NettyDataBuffer[].class);
-
-				ByteBuf[] nativeBuffers =
-						Arrays.stream(copy).map(NettyDataBuffer::getNativeBuffer)
-								.toArray(ByteBuf[]::new);
+				ByteBuf[] nativeBuffers = Arrays.stream(buffers)
+						.map(b -> ((NettyDataBuffer) b).getNativeBuffer())
+						.toArray(ByteBuf[]::new);
 
 				write(nativeBuffers);
 			}
@@ -149,7 +146,7 @@ public class NettyDataBuffer implements DataBuffer {
 				new CompositeByteBuf(this.byteBuf.alloc(), this.byteBuf.isDirect(),
 						byteBufs.length + 1);
 		composite.addComponent(this.byteBuf);
-		Arrays.stream(byteBufs).forEach(composite::addComponent);
+		composite.addComponents(byteBufs);
 
 		int writerIndex = this.byteBuf.readableBytes() +
 				Arrays.stream(byteBufs).mapToInt(ByteBuf::readableBytes).sum();

spring-web-reactive/src/main/java/org/springframework/core/io/buffer/NettyDataBufferAllocator.java

@@ -25,7 +25,7 @@ import io.netty.buffer.Unpooled;
 import org.springframework.util.Assert;
 
 /**
- * Implemtation of the {@code DataBufferAllocator} interface based on a Netty
+ * Implementation of the {@code DataBufferAllocator} interface based on a Netty
  * {@link ByteBufAllocator}.
  *
  * @author Arjen Poutsma

spring-web-reactive/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java

@@ -48,8 +48,8 @@ public class DataBufferTests {
 				{new NettyDataBufferAllocator(new UnpooledByteBufAllocator(false))},
 				{new NettyDataBufferAllocator(new PooledByteBufAllocator(true))},
 				{new NettyDataBufferAllocator(new PooledByteBufAllocator(false))},
-				{new DefaultDataBufferAllocator(), true},
-				{new DefaultDataBufferAllocator(), false}};
+				{new DefaultDataBufferAllocator(true)},
+				{new DefaultDataBufferAllocator(false)}};
 	}
 
 	private DataBuffer createDataBuffer(int capacity) {