Implement additional micro performance optimizations

See gh-34717

spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/BeanNameAutoProxyCreator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -114,10 +114,10 @@ public class BeanNameAutoProxyCreator extends AbstractAutoProxyCreator {
 			boolean isFactoryBean = FactoryBean.class.isAssignableFrom(beanClass);
 			for (String mappedName : this.beanNames) {
 				if (isFactoryBean) {
-					if (!mappedName.startsWith(BeanFactory.FACTORY_BEAN_PREFIX)) {
+					if (mappedName.isEmpty() || mappedName.charAt(0) != BeanFactory.FACTORY_BEAN_PREFIX_CHAR) {
 						continue;
 					}
-					mappedName = mappedName.substring(BeanFactory.FACTORY_BEAN_PREFIX.length());
+					mappedName = mappedName.substring(1);  // length of '&'
 				}
 				if (isMatch(beanName, mappedName)) {
 					return true;

spring-beans/src/main/java/org/springframework/beans/factory/BeanFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -124,9 +124,16 @@ public interface BeanFactory {
 	 * beans <i>created</i> by the FactoryBean. For example, if the bean named
 	 * {@code myJndiObject} is a FactoryBean, getting {@code &myJndiObject}
 	 * will return the factory, not the instance returned by the factory.
+	 * @see #FACTORY_BEAN_PREFIX_CHAR
 	 */
 	String FACTORY_BEAN_PREFIX = "&";
 
+	/**
+	 * Character variant of {@link #FACTORY_BEAN_PREFIX}.
+	 * @since 6.2.6
+	 */
+	char FACTORY_BEAN_PREFIX_CHAR = '&';
+
 
 	/**
 	 * Return an instance, which may be shared or independent, of the specified bean.

spring-beans/src/main/java/org/springframework/beans/factory/BeanFactoryUtils.java

@@ -64,14 +64,6 @@ public abstract class BeanFactoryUtils {
 	private static final Map<String, String> transformedBeanNameCache = new ConcurrentHashMap<>();
 
 
-	/**
-	 * Used to dereference a {@link FactoryBean} instance and distinguish it from
-	 * beans <i>created</i> by the FactoryBean. For example, if the bean named
-	 * {@code myJndiObject} is a FactoryBean, getting {@code &myJndiObject}
-	 * will return the factory, not the instance returned by the factory.
-	 */
-	private static final char FACTORY_BEAN_PREFIX = BeanFactory.FACTORY_BEAN_PREFIX.charAt(0);
-
 	/**
 	 * Return whether the given name is a factory dereference
 	 * (beginning with the factory dereference prefix).
@@ -92,14 +84,14 @@ public abstract class BeanFactoryUtils {
 	 */
 	public static String transformedBeanName(String name) {
 		Assert.notNull(name, "'name' must not be null");
-		if (!isFactoryDereference(name)) {
+		if (name.isEmpty() || name.charAt(0) != BeanFactory.FACTORY_BEAN_PREFIX_CHAR) {
 			return name;
 		}
 		return transformedBeanNameCache.computeIfAbsent(name, beanName -> {
 			do {
-				beanName = beanName.substring(BeanFactory.FACTORY_BEAN_PREFIX.length());
+				beanName = beanName.substring(1);  // length of '&'
 			}
-			while (isFactoryDereference(beanName));
+			while (beanName.charAt(0) == BeanFactory.FACTORY_BEAN_PREFIX_CHAR);
 			return beanName;
 		});
 	}

spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanFactory.java

@@ -770,16 +770,16 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 	public String[] getAliases(String name) {
 		String beanName = transformedBeanName(name);
 		List<String> aliases = new ArrayList<>();
-		boolean factoryPrefix = name.startsWith(FACTORY_BEAN_PREFIX);
+		boolean hasFactoryPrefix = (!name.isEmpty() && name.charAt(0) == BeanFactory.FACTORY_BEAN_PREFIX_CHAR);
 		String fullBeanName = beanName;
-		if (factoryPrefix) {
+		if (hasFactoryPrefix) {
 			fullBeanName = FACTORY_BEAN_PREFIX + beanName;
 		}
 		if (!fullBeanName.equals(name)) {
 			aliases.add(fullBeanName);
 		}
 		String[] retrievedAliases = super.getAliases(beanName);
-		String prefix = (factoryPrefix ? FACTORY_BEAN_PREFIX : "");
+		String prefix = (hasFactoryPrefix ? FACTORY_BEAN_PREFIX : "");
 		for (String retrievedAlias : retrievedAliases) {
 			String alias = prefix + retrievedAlias;
 			if (!alias.equals(name)) {
@@ -1292,7 +1292,7 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 	 */
 	protected String originalBeanName(String name) {
 		String beanName = transformedBeanName(name);
-		if (name.startsWith(FACTORY_BEAN_PREFIX)) {
+		if (!name.isEmpty() && name.charAt(0) == BeanFactory.FACTORY_BEAN_PREFIX_CHAR) {
 			beanName = FACTORY_BEAN_PREFIX + beanName;
 		}
 		return beanName;

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassEnhancer.java

@@ -364,9 +364,9 @@ class ConfigurationClassEnhancer {
 			// proxy that intercepts calls to getObject() and returns any cached bean instance.
 			// This ensures that the semantics of calling a FactoryBean from within @Bean methods
 			// is the same as that of referring to a FactoryBean within XML. See SPR-6602.
-			if (factoryContainsBean(beanFactory, BeanFactory.FACTORY_BEAN_PREFIX + beanName) &&
-					factoryContainsBean(beanFactory, beanName)) {
-				Object factoryBean = beanFactory.getBean(BeanFactory.FACTORY_BEAN_PREFIX + beanName);
+			String factoryBeanName = BeanFactory.FACTORY_BEAN_PREFIX + beanName;
+			if (factoryContainsBean(beanFactory, factoryBeanName) && factoryContainsBean(beanFactory, beanName)) {
+				Object factoryBean = beanFactory.getBean(factoryBeanName);
 				if (factoryBean instanceof ScopedProxyFactoryBean) {
 					// Scoped proxy factory beans are a special case and should not be further proxied
 				}

spring-context/src/main/java/org/springframework/jmx/export/MBeanExporter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -932,8 +932,8 @@ public class MBeanExporter extends MBeanRegistrationSupport implements MBeanExpo
 	 */
 	private boolean isExcluded(String beanName) {
 		return (this.excludedBeans.contains(beanName) ||
-					(beanName.startsWith(BeanFactory.FACTORY_BEAN_PREFIX) &&
-							this.excludedBeans.contains(beanName.substring(BeanFactory.FACTORY_BEAN_PREFIX.length()))));
+					(!beanName.isEmpty() && (beanName.charAt(0) == BeanFactory.FACTORY_BEAN_PREFIX_CHAR) &&
+							this.excludedBeans.contains(beanName.substring(1))));  // length of '&'
 	}
 
 	/**