Please use 'MongoMappingContext#setAutoIndexCreation(boolean)' or override 'MongoConfigurationSuppor

Disable auto index creation in application.properties file

spring.data.mongodb.auto-index-creation=false

or application.yml file

spring:
  data:
    mongodb:
      auto-index-creation: false

Create the class MongoConfiguration whit @Configuration annotation

Injetc this dependencies

private final MongoTemplate mongoTemplate;
private final MongoConverter mongoConverter;

and add this method

@EventListener(ApplicationReadyEvent.class)
public void initIndicesAfterStartup() {

    log.info("Mongo InitIndicesAfterStartup init");
    var init = System.currentTimeMillis();

    var mappingContext = this.mongoConverter.getMappingContext();

    if (mappingContext instanceof MongoMappingContext) {
        MongoMappingContext mongoMappingContext = (MongoMappingContext) mappingContext;
        for (BasicMongoPersistentEntity<?> persistentEntity : mongoMappingContext.getPersistentEntities()) {
            var clazz = persistentEntity.getType();
            if (clazz.isAnnotationPresent(Document.class)) {
                var resolver = new MongoPersistentEntityIndexResolver(mongoMappingContext);

                var indexOps = mongoTemplate.indexOps(clazz);
                resolver.resolveIndexFor(clazz).forEach(indexOps::ensureIndex);
            }
        }
    }

    log.info("Mongo InitIndicesAfterStartup take: {}", (System.currentTimeMillis() - init));
}

remember that var is only for java 11+

The final class, which uses Lombok

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.event.EventListener;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.convert.MongoConverter;
import org.springframework.data.mongodb.core.index.MongoPersistentEntityIndexResolver;
import org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity;
import org.springframework.data.mongodb.core.mapping.Document;
import org.springframework.data.mongodb.core.mapping.MongoMappingContext;


@Slf4j
@RequiredArgsConstructor
@Configuration
public class MongoConfiguration {

private final MongoTemplate mongoTemplate;

private final MongoConverter mongoConverter;

@EventListener(ApplicationReadyEvent.class)
public void initIndicesAfterStartup() {

        log.info("Mongo InitIndicesAfterStartup init");
        var init = System.currentTimeMillis();

        var mappingContext = this.mongoConverter.getMappingContext();

        if (mappingContext instanceof MongoMappingContext) {
            MongoMappingContext mongoMappingContext = (MongoMappingContext) mappingContext;
            for (BasicMongoPersistentEntity<?> persistentEntity : mongoMappingContext.getPersistentEntities()) {
                var clazz = persistentEntity.getType();
                if (clazz.isAnnotationPresent(Document.class)) {
                    var resolver = new MongoPersistentEntityIndexResolver(mongoMappingContext);

                    var indexOps = mongoTemplate.indexOps(clazz);
                    resolver.resolveIndexFor(clazz).forEach(indexOps::ensureIndex);
                }
            }
        }

        log.info("Mongo InitIndicesAfterStartup take: {}", (System.currentTimeMillis() - init));
    }

}