Merge branch '5.3.x'

# Conflicts:
#	spring-context/spring-context.gradle
#	spring-core/src/main/java/org/springframework/core/ReactiveAdapterRegistry.java

spring-aop/src/main/java/org/springframework/aop/framework/CglibAopProxy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -237,7 +237,7 @@ class CglibAopProxy implements AopProxy, Serializable {
 	 * validates it if not.
 	 */
 	private void validateClassIfNecessary(Class<?> proxySuperClass, @Nullable ClassLoader proxyClassLoader) {
-		if (logger.isWarnEnabled()) {
+		if (!this.advised.isOptimize() && logger.isInfoEnabled()) {
 			synchronized (validatedClasses) {
 				if (!validatedClasses.containsKey(proxySuperClass)) {
 					doValidateClass(proxySuperClass, proxyClassLoader,

spring-aop/src/main/java/org/springframework/aop/framework/ProxyConfig.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -73,11 +73,9 @@ public class ProxyConfig implements Serializable {
 	 * The exact meaning of "aggressive optimizations" will differ
 	 * between proxies, but there is usually some tradeoff.
 	 * Default is "false".
-	 * <p>For example, optimization will usually mean that advice changes won't
-	 * take effect after a proxy has been created. For this reason, optimization
-	 * is disabled by default. An optimize value of "true" may be ignored
-	 * if other settings preclude optimization: for example, if "exposeProxy"
-	 * is set to "true" and that's not compatible with the optimization.
+	 * <p>With Spring's current proxy options, this flag effectively
+	 * enforces CGLIB proxies (similar to {@link #setProxyTargetClass})
+	 * but without any class validation checks (for final methods etc).
 	 */
 	public void setOptimize(boolean optimize) {
 		this.optimize = optimize;

spring-context/src/main/java/org/springframework/context/expression/StandardBeanExpressionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -24,6 +24,7 @@ import org.springframework.beans.factory.BeanExpressionException;
 import org.springframework.beans.factory.config.BeanExpressionContext;
 import org.springframework.beans.factory.config.BeanExpressionResolver;
 import org.springframework.core.convert.ConversionService;
+import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ExpressionParser;
 import org.springframework.expression.ParserContext;
@@ -156,10 +157,10 @@ public class StandardBeanExpressionResolver implements BeanExpressionResolver {
 				sec.addPropertyAccessor(new EnvironmentAccessor());
 				sec.setBeanResolver(new BeanFactoryResolver(evalContext.getBeanFactory()));
 				sec.setTypeLocator(new StandardTypeLocator(evalContext.getBeanFactory().getBeanClassLoader()));
-				ConversionService conversionService = evalContext.getBeanFactory().getConversionService();
-				if (conversionService != null) {
-					sec.setTypeConverter(new StandardTypeConverter(conversionService));
-				}
+				sec.setTypeConverter(new StandardTypeConverter(() -> {
+					ConversionService cs = evalContext.getBeanFactory().getConversionService();
+					return (cs != null ? cs : DefaultConversionService.getSharedInstance());
+				}));
 				customizeEvaluationContext(sec);
 				this.evaluationCache.put(evalContext, sec);
 			}

spring-context/src/test/java/org/springframework/context/annotation/ConfigurationClassPostConstructAndAutowiringTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -24,7 +24,6 @@ import org.springframework.beans.testfixture.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-
 /**
  * Tests cornering the issue reported in SPR-8080. If the product of a @Bean method
  * was @Autowired into a configuration class while at the same time the declaring
@@ -33,7 +32,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * 'currently in creation' status of the autowired bean and result in creating multiple
  * instances of the given @Bean, violating container scoping / singleton semantics.
  *
- * This is resolved through no longer relying on 'currently in creation' status, but
+ * <p>This is resolved through no longer relying on 'currently in creation' status, but
  * rather on a thread local that informs the enhanced bean method implementation whether
  * the factory is the caller or not.
  *

spring-core/src/main/java/org/springframework/asm/ClassReader.java

@@ -324,7 +324,9 @@ public class ClassReader {
       }
       outputStream.flush();
       if (readCount == 1) {
-        return data;
+        // SPRING PATCH: some misbehaving InputStreams return -1 but still write to buffer (gh-27429)
+        // return data;
+        // END OF PATCH
       }
       return outputStream.toByteArray();
     } finally {

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

@@ -275,6 +275,7 @@ public class ReactiveAdapterRegistry {
 		}
 	}
 
+
 	private static class RxJava3Registrar {
 
 		void registerAdapters(ReactiveAdapterRegistry registry) {

spring-expression/src/main/java/org/springframework/expression/spel/support/StandardTypeConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.expression.spel.support;
 
+import java.util.function.Supplier;
+
 import org.springframework.core.convert.ConversionException;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.TypeDescriptor;
@@ -37,7 +39,7 @@ import org.springframework.util.Assert;
  */
 public class StandardTypeConverter implements TypeConverter {
 
-	private final ConversionService conversionService;
+	private final Supplier<ConversionService> conversionService;
 
 
 	/**
@@ -45,7 +47,7 @@ public class StandardTypeConverter implements TypeConverter {
 	 * @see DefaultConversionService#getSharedInstance()
 	 */
 	public StandardTypeConverter() {
-		this.conversionService = DefaultConversionService.getSharedInstance();
+		this.conversionService = DefaultConversionService::getSharedInstance;
 	}
 
 	/**
@@ -54,20 +56,30 @@ public class StandardTypeConverter implements TypeConverter {
 	 */
 	public StandardTypeConverter(ConversionService conversionService) {
 		Assert.notNull(conversionService, "ConversionService must not be null");
+		this.conversionService = () -> conversionService;
+	}
+
+	/**
+	 * Create a StandardTypeConverter for the given ConversionService.
+	 * @param conversionService a Supplier for the ConversionService to delegate to
+	 * @since 5.3.11
+	 */
+	public StandardTypeConverter(Supplier<ConversionService> conversionService) {
+		Assert.notNull(conversionService, "Supplier must not be null");
 		this.conversionService = conversionService;
 	}
 
 
 	@Override
 	public boolean canConvert(@Nullable TypeDescriptor sourceType, TypeDescriptor targetType) {
-		return this.conversionService.canConvert(sourceType, targetType);
+		return this.conversionService.get().canConvert(sourceType, targetType);
 	}
 
 	@Override
 	@Nullable
 	public Object convertValue(@Nullable Object value, @Nullable TypeDescriptor sourceType, TypeDescriptor targetType) {
 		try {
-			return this.conversionService.convert(value, sourceType, targetType);
+			return this.conversionService.get().convert(value, sourceType, targetType);
 		}
 		catch (ConversionException ex) {
 			throw new SpelEvaluationException(ex, SpelMessage.TYPE_CONVERSION_ERROR,