Current implementation of getCacheKey uses string concatenation: https://github.com/spring-projects/spring-framework/blob/master/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java#L306-L308
This leads to two problems:
1) Excessive heap garbage due to throw-away string creation
2) Excessive CPU due to computing hash code for the newly created strings.
It our problem that legacy part of system use BeanFactory.getBean instead of inject dependency correctly. But problem described above also affect application start time because spring for inject dependency also do getBean by Class and as result spring for each class iterate by all beans in context and generate cache key like: