Construct StringWriter instances with appropriate initial size

Closes gh-25789

(cherry picked from commit 9dfef59)

Author: jhoeller

spring-context-support/src/main/java/org/springframework/ui/freemarker/FreeMarkerTemplateUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,7 +46,7 @@ public abstract class FreeMarkerTemplateUtils {
 	public static String processTemplateIntoString(Template template, Object model)
 			throws IOException, TemplateException {
 
-		StringWriter result = new StringWriter();
+		StringWriter result = new StringWriter(1024);
 		template.process(model, result);
 		return result.toString();
 	}

spring-core/src/main/java/org/springframework/util/FileCopyUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -181,15 +181,15 @@ public static int copy(Reader in, Writer out) throws IOException {
 		Assert.notNull(out, "No Writer specified");
 
 		try {
-			int byteCount = 0;
+			int charCount = 0;
 			char[] buffer = new char[BUFFER_SIZE];
-			int bytesRead = -1;
-			while ((bytesRead = in.read(buffer)) != -1) {
-				out.write(buffer, 0, bytesRead);
-				byteCount += bytesRead;
+			int charsRead;
+			while ((charsRead = in.read(buffer)) != -1) {
+				out.write(buffer, 0, charsRead);
+				charCount += charsRead;
 			}
 			out.flush();
-			return byteCount;
+			return charCount;
 		}
 		finally {
 			try {
@@ -206,7 +206,7 @@ public static int copy(Reader in, Writer out) throws IOException {
 	}
 
 	/**
-	 * Copy the contents of the given String to the given output Writer.
+	 * Copy the contents of the given String to the given Writer.
 	 * Closes the writer when done.
 	 * @param in the String to copy from
 	 * @param out the Writer to copy to
@@ -240,7 +240,7 @@ public static String copyToString(@Nullable Reader in) throws IOException {
 			return "";
 		}
 
-		StringWriter out = new StringWriter();
+		StringWriter out = new StringWriter(BUFFER_SIZE);
 		copy(in, out);
 		return out.toString();
 	}

spring-jms/src/main/java/org/springframework/jms/support/converter/MappingJackson2MessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -275,7 +275,7 @@ protected Message toMessage(Object object, Session session, ObjectWriter objectW
 	protected TextMessage mapToTextMessage(Object object, Session session, ObjectWriter objectWriter)
 			throws JMSException, IOException {
 
-		StringWriter writer = new StringWriter();
+		StringWriter writer = new StringWriter(1024);
 		objectWriter.writeValue(writer, object);
 		return session.createTextMessage(writer.toString());
 	}

spring-jms/src/main/java/org/springframework/jms/support/converter/MarshallingMessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,8 +48,6 @@
  * @author Arjen Poutsma
  * @author Juergen Hoeller
  * @since 3.0
- * @see org.springframework.jms.core.JmsTemplate#convertAndSend
- * @see org.springframework.jms.core.JmsTemplate#receiveAndConvert
  */
 public class MarshallingMessageConverter implements MessageConverter, InitializingBean {
 
@@ -215,7 +213,7 @@ else if (message instanceof BytesMessage) {
 	protected TextMessage marshalToTextMessage(Object object, Session session, Marshaller marshaller)
 			throws JMSException, IOException, XmlMappingException {
 
-		StringWriter writer = new StringWriter();
+		StringWriter writer = new StringWriter(1024);
 		Result result = new StreamResult(writer);
 		marshaller.marshal(object, result);
 		return session.createTextMessage(writer.toString());

spring-messaging/src/main/java/org/springframework/messaging/converter/MappingJackson2MessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -211,9 +211,11 @@ protected Object convertFromInternal(Message<?> message, Class<?> targetClass, @
 		JavaType javaType = getJavaType(targetClass, conversionHint);
 		Object payload = message.getPayload();
 		Class<?> view = getSerializationView(conversionHint);
-		// Note: in the view case, calling withType instead of forType for compatibility with Jackson <2.5
 		try {
-			if (payload instanceof byte[]) {
+			if (targetClass.isInstance(payload)) {
+				return payload;
+			}
+			else if (payload instanceof byte[]) {
 				if (view != null) {
 					return this.objectMapper.readerWithView(view).forType(javaType).readValue((byte[]) payload);
 				}
@@ -222,6 +224,7 @@ protected Object convertFromInternal(Message<?> message, Class<?> targetClass, @
 				}
 			}
 			else {
+				// Assuming a text-based source payload
 				if (view != null) {
 					return this.objectMapper.readerWithView(view).forType(javaType).readValue(payload.toString());
 				}
@@ -270,7 +273,8 @@ protected Object convertToInternal(Object payload, @Nullable MessageHeaders head
 				payload = out.toByteArray();
 			}
 			else {
-				Writer writer = new StringWriter();
+				// Assuming a text-based target payload
+				Writer writer = new StringWriter(1024);
 				if (view != null) {
 					this.objectMapper.writerWithView(view).writeValue(writer, payload);
 				}

spring-messaging/src/main/java/org/springframework/messaging/converter/MarshallingMessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -173,13 +173,13 @@ protected Object convertToInternal(Object payload, @Nullable MessageHeaders head
 		Assert.notNull(this.marshaller, "Property 'marshaller' is required");
 		try {
 			if (byte[].class == getSerializedPayloadClass()) {
-				ByteArrayOutputStream out = new ByteArrayOutputStream();
+				ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
 				Result result = new StreamResult(out);
 				this.marshaller.marshal(payload, result);
 				payload = out.toByteArray();
 			}
 			else {
-				Writer writer = new StringWriter();
+				Writer writer = new StringWriter(1024);
 				Result result = new StreamResult(writer);
 				this.marshaller.marshal(payload, result);
 				payload = writer.toString();