GH-9745: IntEvalCtxFB: Use BeanFactory's ClassLoader

Fixes: #9745
Issue link: #9745

The `IntegrationEvaluationContextFactoryBean` does not provide a `TypeLocator` by default.
That may lead to a class-not-found problem from different `ClassLoader` in the parallel Java `Stream` executor.

* Fix `IntegrationEvaluationContextFactoryBean` to use a `StandardTypeLocator` based on the `applicationContext.getClassLoader()`

(cherry picked from commit 6184c40)

# Conflicts:
#	spring-integration-core/src/main/java/org/springframework/integration/config/IntegrationEvaluationContextFactoryBean.java

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/config/IntegrationEvaluationContextFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2019 the original author or authors.
+ * Copyright 2013-2025 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.
@@ -20,13 +20,16 @@
 import java.util.Map.Entry;
 
 import org.springframework.beans.factory.FactoryBean;
+import org.springframework.context.ApplicationContext;
 import org.springframework.context.expression.BeanFactoryResolver;
 import org.springframework.context.expression.MapAccessor;
 import org.springframework.expression.BeanResolver;
 import org.springframework.expression.PropertyAccessor;
 import org.springframework.expression.TypeLocator;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
+import org.springframework.expression.spel.support.StandardTypeLocator;
 import org.springframework.integration.context.IntegrationContextUtils;
+import org.springframework.lang.Nullable;
 
 /**
  * <p>
@@ -65,7 +68,8 @@
 public class IntegrationEvaluationContextFactoryBean extends AbstractEvaluationContextFactoryBean
 		implements FactoryBean<StandardEvaluationContext> {
 
-	private volatile TypeLocator typeLocator;
+	@Nullable
+	private TypeLocator typeLocator;
 
 	private BeanResolver beanResolver;
 
@@ -80,8 +84,12 @@ public boolean isSingleton() {
 
 	@Override
 	public void afterPropertiesSet() {
-		if (getApplicationContext() != null) {
-			this.beanResolver = new BeanFactoryResolver(getApplicationContext());
+		ApplicationContext applicationContext = getApplicationContext();
+		if (applicationContext != null) {
+			this.beanResolver = new BeanFactoryResolver(applicationContext);
+			if (this.typeLocator == null) {
+				this.typeLocator = new StandardTypeLocator(applicationContext.getClassLoader());
+			}
 		}
 		initialize(IntegrationContextUtils.INTEGRATION_EVALUATION_CONTEXT_BEAN_NAME);
 	}