diff --git a/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Decoder.java b/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Decoder.java
index aa346306c3..f5f2690256 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Decoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Decoder.java
@@ -38,6 +38,7 @@ import org.springframework.core.codec.CodecException;
 import org.springframework.core.codec.DecodingException;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.codec.HttpMessageDecoder;
 import org.springframework.http.server.reactive.ServerHttpRequest;
@@ -88,56 +89,73 @@ public abstract class AbstractJackson2Decoder extends Jackson2CodecSupport imple
 
 		Flux<TokenBuffer> tokens = Jackson2Tokenizer.tokenize(
 				Flux.from(input), this.jsonFactory, getObjectMapper(), true);
-		return decodeInternal(tokens, elementType, mimeType, hints);
+
+		ObjectReader reader = getObjectReader(elementType, hints);
+
+		return tokens.handle((tokenBuffer, sink) -> {
+			try {
+				Object value = reader.readValue(tokenBuffer.asParser(getObjectMapper()));
+				logValue(value, hints);
+				if (value != null) {
+					sink.next(value);
+				}
+			}
+			catch (IOException ex) {
+				sink.error(processException(ex));
+			}
+		});
 	}
 
 	@Override
 	public Mono<Object> decodeToMono(Publisher<DataBuffer> input, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 
-		Flux<TokenBuffer> tokens = Jackson2Tokenizer.tokenize(
-				Flux.from(input), this.jsonFactory, getObjectMapper(), false);
-		return decodeInternal(tokens, elementType, mimeType, hints).singleOrEmpty();
+		return DataBufferUtils.join(input).map(dataBuffer -> {
+			try {
+				ObjectReader objectReader = getObjectReader(elementType, hints);
+				Object value = objectReader.readValue(dataBuffer.asInputStream());
+				logValue(value, hints);
+				return value;
+			}
+			catch (IOException ex) {
+				throw processException(ex);
+			}
+			finally {
+				DataBufferUtils.release(dataBuffer);
+			}
+		});
 	}
 
-	private Flux<Object> decodeInternal(Flux<TokenBuffer> tokens, ResolvableType elementType,
-			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
-
-		Assert.notNull(tokens, "'tokens' must not be null");
+	private ObjectReader getObjectReader(ResolvableType elementType, @Nullable Map<String, Object> hints) {
 		Assert.notNull(elementType, "'elementType' must not be null");
-
 		MethodParameter param = getParameter(elementType);
 		Class<?> contextClass = (param != null ? param.getContainingClass() : null);
 		JavaType javaType = getJavaType(elementType.getType(), contextClass);
 		Class<?> jsonView = (hints != null ? (Class<?>) hints.get(Jackson2CodecSupport.JSON_VIEW_HINT) : null);
-
-		ObjectReader reader = (jsonView != null ?
+		return jsonView != null ?
 				getObjectMapper().readerWithView(jsonView).forType(javaType) :
-				getObjectMapper().readerFor(javaType));
+				getObjectMapper().readerFor(javaType);
+	}
 
-		return tokens.handle((tokenBuffer, sink) -> {
-			try {
-				Object value = reader.readValue(tokenBuffer.asParser(getObjectMapper()));
-				if (!Hints.isLoggingSuppressed(hints)) {
-					LogFormatUtils.traceDebug(logger, traceOn -> {
-						String formatted = LogFormatUtils.formatValue(value, !traceOn);
-						return Hints.getLogPrefix(hints) + "Decoded [" + formatted + "]";
-					});
-				}
-				if (value != null) {
-					sink.next(value);
-				}
-			}
-			catch (InvalidDefinitionException ex) {
-				sink.error(new CodecException("Type definition error: " + ex.getType(), ex));
-			}
-			catch (JsonProcessingException ex) {
-				sink.error(new DecodingException("JSON decoding error: " + ex.getOriginalMessage(), ex));
-			}
-			catch (IOException ex) {
-				sink.error(new DecodingException("I/O error while parsing input stream", ex));
-			}
-		});
+	private void logValue(@Nullable Object value, @Nullable Map<String, Object> hints) {
+		if (!Hints.isLoggingSuppressed(hints)) {
+			LogFormatUtils.traceDebug(logger, traceOn -> {
+				String formatted = LogFormatUtils.formatValue(value, !traceOn);
+				return Hints.getLogPrefix(hints) + "Decoded [" + formatted + "]";
+			});
+		}
+	}
+
+	private CodecException processException(IOException ex) {
+		if (ex instanceof InvalidDefinitionException) {
+			JavaType type = ((InvalidDefinitionException) ex).getType();
+			return new CodecException("Type definition error: " + type, ex);
+		}
+		if (ex instanceof JsonProcessingException) {
+			String originalMessage = ((JsonProcessingException) ex).getOriginalMessage();
+			return new DecodingException("JSON decoding error: " + originalMessage, ex);
+		}
+		return new DecodingException("I/O error while parsing input stream", ex);
 	}
 
 
diff --git a/spring-web/src/main/java/org/springframework/http/codec/xml/Jaxb2XmlDecoder.java b/spring-web/src/main/java/org/springframework/http/codec/xml/Jaxb2XmlDecoder.java
index ab63d30741..04227f73e2 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/xml/Jaxb2XmlDecoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/xml/Jaxb2XmlDecoder.java
@@ -17,6 +17,7 @@
 package org.springframework.http.codec.xml;
 
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.function.BiConsumer;
@@ -31,9 +32,12 @@ import javax.xml.bind.annotation.XmlSchema;
 import javax.xml.bind.annotation.XmlType;
 import javax.xml.namespace.QName;
 import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
 import javax.xml.stream.events.XMLEvent;
 
 import org.reactivestreams.Publisher;
+import reactor.core.Exceptions;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.core.publisher.SynchronousSink;
@@ -44,6 +48,7 @@ import org.springframework.core.codec.CodecException;
 import org.springframework.core.codec.DecodingException;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.log.LogFormatUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -72,6 +77,8 @@ public class Jaxb2XmlDecoder extends AbstractDecoder<Object> {
 	 */
 	private static final String JAXB_DEFAULT_ANNOTATION_VALUE = "##default";
 
+	private static final XMLInputFactory inputFactory = StaxUtils.createDefensiveInputFactory();
+
 
 	private final XmlEventDecoder xmlEventDecoder = new XmlEventDecoder();
 
@@ -132,10 +139,24 @@ public class Jaxb2XmlDecoder extends AbstractDecoder<Object> {
 	}
 
 	@Override
-	public Mono<Object> decodeToMono(Publisher<DataBuffer> inputStream, ResolvableType elementType,
+	@SuppressWarnings({"rawtypes", "unchecked", "cast"})  // XMLEventReader is Iterator<Object> on JDK 9
+	public Mono<Object> decodeToMono(Publisher<DataBuffer> input, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 
-		return decode(inputStream, elementType, mimeType, hints).singleOrEmpty();
+		return DataBufferUtils.join(input).map(dataBuffer -> {
+			try {
+				Iterator eventReader = inputFactory.createXMLEventReader(dataBuffer.asInputStream());
+				List<XMLEvent> events = new ArrayList<>();
+				eventReader.forEachRemaining(event -> events.add((XMLEvent) event));
+				return unmarshal(events, elementType.toClass());
+			}
+			catch (XMLStreamException ex) {
+				throw Exceptions.propagate(ex);
+			}
+			finally {
+				DataBufferUtils.release(dataBuffer);
+			}
+		});
 	}
 
 	private Object unmarshal(List<XMLEvent> events, Class<?> outputClass) {
diff --git a/spring-web/src/main/java/org/springframework/http/codec/xml/XmlEventDecoder.java b/spring-web/src/main/java/org/springframework/http/codec/xml/XmlEventDecoder.java
index d44ff23a11..b417de7610 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/xml/XmlEventDecoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/xml/XmlEventDecoder.java
@@ -95,7 +95,7 @@ public class XmlEventDecoder extends AbstractDecoder<XMLEvent> {
 
 
 	@Override
-	@SuppressWarnings({"rawtypes", "unchecked", "cast"})  // on JDK 9 where XMLEventReader is Iterator<Object> instead of simply Iterator
+	@SuppressWarnings({"rawtypes", "unchecked", "cast"})  // XMLEventReader is Iterator<Object> on JDK 9
 	public Flux<XMLEvent> decode(Publisher<DataBuffer> input, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {