2 implementations of CachingConfigurer were found when only 1 was expected. Refactor the configuration such that CachingConfigurer is implemented only once or not at all.

This error message occurs when there are multiple implementations of the CachingConfigurer interface in the Spring application context. To resolve this issue, you need to refactor your configuration so that CachingConfigurer is implemented only once or not at all.

One approach to resolve this issue is to remove the redundant implementation of CachingConfigurer from your configuration. Another approach is to merge the implementations into a single class that implements the CachingConfigurer interface.

Here is an example of how to merge the implementations:

@Configuration
@EnableCaching
public class CacheConfig implements CachingConfigurer {

    @Override
    public CacheManager cacheManager() {
        //...
    }

    @Override
    public KeyGenerator keyGenerator() {
        //...
    }

    @Override
    public CacheResolver cacheResolver() {
        //...
    }

    @Override
    public CacheErrorHandler errorHandler() {
        //...
    }
}

In this example, the CacheConfig class implements the CachingConfigurer interface and provides the necessary implementations for its methods. By doing so, you can ensure that there is only one implementation of CachingConfigurer in the application context and avoid the "2 implementations of CachingConfigurer were found when only 1 was expected" error message.