Replace remaining use of StringBuffer with StringBuilder

Although this commit only applies to test classes, it serves to reduce
the noise when searching for undesirable usage of StringBuffer in
production code.

spring-aop/src/test/java/org/springframework/aop/aspectj/annotation/AbstractAspectJAdvisorFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -322,7 +322,7 @@ abstract class AbstractAspectJAdvisorFactoryTests {
 		int b = 12;
 		int c = 25;
 		String d = "d";
-		StringBuffer e = new StringBuffer("stringbuf");
+		StringBuilder e = new StringBuilder("stringbuf");
 		String expectedResult = a + b+ c + d + e;
 		assertThat(mva.mungeArgs(a, b, c, d, e)).isEqualTo(expectedResult);
 	}
@@ -728,12 +728,12 @@ abstract class AbstractAspectJAdvisorFactoryTests {
 	@Aspect
 	static class ManyValuedArgs {
 
-		String mungeArgs(String a, int b, int c, String d, StringBuffer e) {
+		String mungeArgs(String a, int b, int c, String d, StringBuilder e) {
 			return a + b + c + d + e;
 		}
 
 		@Around(value="execution(String mungeArgs(..)) && args(a, b, c, d, e)", argNames="b,c,d,e,a")
-		String reverseAdvice(ProceedingJoinPoint pjp, int b, int c, String d, StringBuffer e, String a) throws Throwable {
+		String reverseAdvice(ProceedingJoinPoint pjp, int b, int c, String d, StringBuilder e, String a) throws Throwable {
 			assertThat(pjp.proceed()).isEqualTo(a + b+ c+ d+ e);
 			return a + b + c + d + e;
 		}

spring-test/src/test/java/org/springframework/test/context/hierarchies/standard/DirtiesContextWithContextHierarchyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -54,10 +54,10 @@ import static org.assertj.core.api.Assertions.assertThat;
 class DirtiesContextWithContextHierarchyTests {
 
 	@Autowired
-	private StringBuffer foo;
+	private StringBuilder foo;
 
 	@Autowired
-	private StringBuffer baz;
+	private StringBuilder baz;
 
 	@Autowired
 	private ApplicationContext context;
@@ -74,7 +74,7 @@ class DirtiesContextWithContextHierarchyTests {
 	@Order(1)
 	void verifyOriginalStateAndDirtyContexts() {
 		assertOriginalState();
-		reverseStringBuffers();
+		reverseStringBuilders();
 	}
 
 	@Test
@@ -90,7 +90,7 @@ class DirtiesContextWithContextHierarchyTests {
 	@DirtiesContext(hierarchyMode = HierarchyMode.CURRENT_LEVEL)
 	void verifyOriginalStateWasReinstatedAndDirtyContextsAndTriggerCurrentLevelCacheClearing() {
 		assertOriginalState();
-		reverseStringBuffers();
+		reverseStringBuilders();
 	}
 
 	@Test
@@ -100,7 +100,7 @@ class DirtiesContextWithContextHierarchyTests {
 		assertCleanChildContext();
 	}
 
-	private void reverseStringBuffers() {
+	private void reverseStringBuilders() {
 		foo.reverse();
 		baz.reverse();
 	}
@@ -131,13 +131,13 @@ class DirtiesContextWithContextHierarchyTests {
 	static class ParentConfig {
 
 		@Bean
-		StringBuffer foo() {
-			return new StringBuffer("foo");
+		StringBuilder foo() {
+			return new StringBuilder("foo");
 		}
 
 		@Bean
-		StringBuffer baz() {
-			return new StringBuffer("baz-parent");
+		StringBuilder baz() {
+			return new StringBuilder("baz-parent");
 		}
 	}
 
@@ -145,8 +145,8 @@ class DirtiesContextWithContextHierarchyTests {
 	static class ChildConfig {
 
 		@Bean
-		StringBuffer baz() {
-			return new StringBuffer("baz-child");
+		StringBuilder baz() {
+			return new StringBuilder("baz-child");
 		}
 	}
 

spring-webmvc/src/test/java/org/springframework/web/context/ContextLoaderTests.java

@@ -96,7 +96,7 @@ class ContextLoaderTests {
 	 */
 	@Test
 	void contextLoaderListenerWithCustomizedContextLoader() {
-		final StringBuffer buffer = new StringBuffer();
+		final StringBuilder builder = new StringBuilder();
 		final String expectedContents = "customizeContext() was called";
 		final MockServletContext sc = new MockServletContext("");
 		sc.addInitParameter(ContextLoader.CONFIG_LOCATION_PARAM,
@@ -107,11 +107,11 @@ class ContextLoaderTests {
 				assertThat(sc).as("The ServletContext should not be null.").isNotNull();
 				assertThat(sc).as("Verifying that we received the expected ServletContext.").isEqualTo(sc);
 				assertThat(wac.isActive()).as("The ApplicationContext should not yet have been refreshed.").isFalse();
-				buffer.append(expectedContents);
+				builder.append(expectedContents);
 			}
 		};
 		listener.contextInitialized(new ServletContextEvent(sc));
-		assertThat(buffer.toString()).as("customizeContext() should have been called.").isEqualTo(expectedContents);
+		assertThat(builder.toString()).as("customizeContext() should have been called.").isEqualTo(expectedContents);
 	}
 
 	@Test

spring-webmvc/src/test/java/org/springframework/web/servlet/tags/HtmlEscapeTagTests.java

@@ -131,7 +131,7 @@ class HtmlEscapeTagTests extends AbstractTagTests {
 	@Test
 	void escapeBody() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer result = new StringBuffer();
+		final StringBuilder result = new StringBuilder();
 		EscapeBodyTag tag = new EscapeBodyTag() {
 			@Override
 			protected String readBodyContent() {
@@ -151,7 +151,7 @@ class HtmlEscapeTagTests extends AbstractTagTests {
 	@Test
 	void escapeBodyWithHtmlEscape() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer result = new StringBuffer();
+		final StringBuilder result = new StringBuilder();
 		EscapeBodyTag tag = new EscapeBodyTag() {
 			@Override
 			protected String readBodyContent() {
@@ -172,7 +172,7 @@ class HtmlEscapeTagTests extends AbstractTagTests {
 	@Test
 	void escapeBodyWithJavaScriptEscape() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer result = new StringBuffer();
+		final StringBuilder result = new StringBuilder();
 		EscapeBodyTag tag = new EscapeBodyTag() {
 			@Override
 			protected String readBodyContent() {
@@ -193,7 +193,7 @@ class HtmlEscapeTagTests extends AbstractTagTests {
 	@Test
 	void escapeBodyWithHtmlEscapeAndJavaScriptEscape() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer result = new StringBuffer();
+		final StringBuilder result = new StringBuilder();
 		EscapeBodyTag tag = new EscapeBodyTag() {
 			@Override
 			protected String readBodyContent() {

spring-webmvc/src/test/java/org/springframework/web/servlet/tags/MessageTagTests.java

@@ -49,7 +49,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithMessageSourceResolvable() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -66,7 +66,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCode() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -83,7 +83,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndArgument() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -101,7 +101,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndArguments() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -119,7 +119,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndStringArgumentWithCustomSeparator() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -138,7 +138,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndArrayArgument() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -156,7 +156,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndObjectArgument() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -174,7 +174,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndArgumentAndNestedArgument() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -193,7 +193,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndNestedArgument() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -211,7 +211,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndNestedArguments() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -230,7 +230,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithCodeAndText() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -248,7 +248,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithText() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -268,7 +268,7 @@ class MessageTagTests extends AbstractTagTests {
 		PageContext pc = createPageContext();
 		pc.getServletContext().setInitParameter(WebUtils.RESPONSE_ENCODED_HTML_ESCAPE_CONTEXT_PARAM, "true");
 		pc.getResponse().setCharacterEncoding("UTF-8");
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -286,7 +286,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithTextAndJavaScriptEscape() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {
@@ -304,7 +304,7 @@ class MessageTagTests extends AbstractTagTests {
 	@Test
 	void messageTagWithTextAndHtmlEscapeAndJavaScriptEscape() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		MessageTag tag = new MessageTag() {
 			@Override
 			protected void writeMessage(String msg) {

spring-webmvc/src/test/java/org/springframework/web/servlet/tags/ThemeTagTests.java

@@ -43,7 +43,7 @@ class ThemeTagTests extends AbstractTagTests {
 	@SuppressWarnings("serial")
 	void themeTag() throws JspException {
 		PageContext pc = createPageContext();
-		final StringBuffer message = new StringBuffer();
+		final StringBuilder message = new StringBuilder();
 		ThemeTag tag = new ThemeTag() {
 			@Override
 			protected void writeMessage(String msg) {