Optimize entity deletion in SimpleJpaRepository.

This change improves the performance of the delete method by first checking if the entity is already managed by the EntityManager. If so, it removes the entity directly without additional database queries. This optimization can reduce unnecessary database lookups in certain scenarios.

Closes #3564

Author: Seol-JY

Diff for: spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java

@@ -93,6 +93,7 @@
  * @author Yanming Zhou
  * @author Ernst-Jan van der Laan
  * @author Diego Krupitza
+ * @author Seol-JY
  */
 @Repository
 @Transactional(readOnly = true)
@@ -196,14 +197,16 @@ public void delete(T entity) {
 
 		Class<?> type = ProxyUtils.getUserClass(entity);
 
-		T existing = (T) entityManager.find(type, entityInformation.getId(entity));
-
-		// if the entity to be deleted doesn't exist, delete is a NOOP
-		if (existing == null) {
+		if (entityManager.contains(entity)) {
+			entityManager.remove(entity);
 			return;
 		}
 
-		entityManager.remove(entityManager.contains(entity) ? entity : entityManager.merge(entity));
+		// if the entity to be deleted doesn't exist, delete is a NOOP
+		T existing = (T) entityManager.find(type, entityInformation.getId(entity));
+		if (existing != null) {
+			entityManager.remove(entityManager.merge(entity));
+		}
 	}
 
 	@Override