Cache SpEL-loaded types in StandardTypeLocator

Closes gh-31579

Author: jhoeller

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

@@ -19,7 +19,10 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
+import org.springframework.core.SmartClassLoader;
 import org.springframework.expression.EvaluationException;
 import org.springframework.expression.TypeLocator;
 import org.springframework.expression.spel.SpelEvaluationException;
@@ -48,6 +51,8 @@ public class StandardTypeLocator implements TypeLocator {
 
 	private final List<String> importPrefixes = new ArrayList<>(1);
 
+	private final Map<String, Class<?>> typeCache = new ConcurrentHashMap<>();
+
 
 	/**
 	 * Create a {@code StandardTypeLocator} for the default {@link ClassLoader}
@@ -110,6 +115,21 @@ public List<String> getImportPrefixes() {
 	 */
 	@Override
 	public Class<?> findType(String typeName) throws EvaluationException {
+		Class<?> cachedType = this.typeCache.get(typeName);
+		if (cachedType != null) {
+			return cachedType;
+		}
+		Class<?> loadedType = loadType(typeName);
+		if (loadedType != null &&
+				!(this.classLoader instanceof SmartClassLoader scl && scl.isClassReloadable(loadedType))) {
+			this.typeCache.put(typeName, loadedType);
+			return loadedType;
+		}
+		throw new SpelEvaluationException(SpelMessage.TYPE_NOT_FOUND, typeName);
+	}
+
+	@Nullable
+	private Class<?> loadType(String typeName) {
 		try {
 			return ClassUtils.forName(typeName, this.classLoader);
 		}
@@ -125,7 +145,7 @@ public Class<?> findType(String typeName) throws EvaluationException {
 				// might be a different prefix
 			}
 		}
-		throw new SpelEvaluationException(SpelMessage.TYPE_NOT_FOUND, typeName);
+		return null;
 	}
 
 }