Simplify String concatenation

spring-beans/src/main/java/org/springframework/beans/factory/config/BeanDefinitionHolder.java

@@ -150,9 +150,7 @@ public class BeanDefinitionHolder implements BeanMetadataElement {
 	 * @see #getBeanDefinition()
 	 */
 	public String getLongDescription() {
-		StringBuilder sb = new StringBuilder(getShortDescription());
-		sb.append(": ").append(this.beanDefinition);
-		return sb.toString();
+		return getShortDescription() + ": " + this.beanDefinition;
 	}
 
 	/**

spring-core/src/main/java/org/springframework/core/ResolvableType.java

@@ -965,13 +965,10 @@ public class ResolvableType implements Serializable {
 				return "?";
 			}
 		}
-		StringBuilder result = new StringBuilder(this.resolved.getName());
 		if (hasGenerics()) {
-			result.append('<');
-			result.append(StringUtils.arrayToDelimitedString(getGenerics(), ", "));
-			result.append('>');
+			return this.resolved.getName() + '<' + StringUtils.arrayToDelimitedString(getGenerics(), ", ") + '>';
 		}
-		return result.toString();
+		return this.resolved.getName();
 	}
 
 

spring-expression/src/main/java/org/springframework/expression/spel/ast/Selection.java

@@ -205,19 +205,16 @@ public class Selection extends SpelNodeImpl {
 
 	@Override
 	public String toStringAST() {
-		StringBuilder sb = new StringBuilder();
+		return prefix() + getChild(0).toStringAST() + "]";
+	}
+
+	private String prefix() {
 		switch (this.variant) {
-			case ALL:
-				sb.append("?[");
-				break;
-			case FIRST:
-				sb.append("^[");
-				break;
-			case LAST:
-				sb.append("$[");
-				break;
+			case ALL:   return "?[";
+			case FIRST: return "^[";
+			case LAST:  return "$[";
 		}
-		return sb.append(getChild(0).toStringAST()).append("]").toString();
+		return "";
 	}
 
 }

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -403,12 +403,11 @@ public class MockHttpServletRequest implements HttpServletRequest {
 
 	private void updateContentTypeHeader() {
 		if (StringUtils.hasLength(this.contentType)) {
-			StringBuilder sb = new StringBuilder(this.contentType);
-			if (!this.contentType.toLowerCase().contains(CHARSET_PREFIX) &&
-					StringUtils.hasLength(this.characterEncoding)) {
-				sb.append(";").append(CHARSET_PREFIX).append(this.characterEncoding);
+			String value = this.contentType;
+			if (StringUtils.hasLength(this.characterEncoding) && !this.contentType.toLowerCase().contains(CHARSET_PREFIX)) {
+				value += ';' + CHARSET_PREFIX + this.characterEncoding;
 			}
-			doAddHeaderValue(HttpHeaders.CONTENT_TYPE, sb.toString(), true);
+			doAddHeaderValue(HttpHeaders.CONTENT_TYPE, value, true);
 		}
 	}
 

spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/AbstractMediaTypeExpression.java

@@ -108,12 +108,10 @@ abstract class AbstractMediaTypeExpression implements Comparable<AbstractMediaTy
 
 	@Override
 	public String toString() {
-		StringBuilder builder = new StringBuilder();
 		if (this.isNegated) {
-			builder.append('!');
+			return '!' + this.mediaType.toString();
 		}
-		builder.append(this.mediaType.toString());
-		return builder.toString();
+		return this.mediaType.toString();
 	}
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/AbstractMediaTypeExpression.java

@@ -92,12 +92,10 @@ abstract class AbstractMediaTypeExpression implements MediaTypeExpression, Compa
 
 	@Override
 	public String toString() {
-		StringBuilder builder = new StringBuilder();
 		if (this.isNegated) {
-			builder.append('!');
+			return '!' + this.mediaType.toString();
 		}
-		builder.append(this.mediaType.toString());
-		return builder.toString();
+		return this.mediaType.toString();
 	}
 
 }