I cannot find back a library that allowed to format log output statements in a much nicer way than what is usually seen. One of the feature I remember is that it could 'offset' the log message depending on the 'nestedness' of where the log statement was occuring.

That is, instead of this:

DEBUG | DefaultBeanDefinitionDocumentReader.java| 86 | Loading bean definitions
DEBUG | AbstractAutowireCapableBeanFactory.java| 411 | Finished creating instance of bean 'MS-SQL'
DEBUG | DefaultSingletonBeanRegistry.java| 213 | Creating shared instance of singleton bean 'MySQL'
DEBUG | AutowireCapableBeanFactory.java| 383 | Creating instance of bean 'MySQL'
DEBUG | AutowireCapableBeanFactory.java| 459 | Eagerly caching bean 'MySQL' to allow for resolving potential circular references
DEBUG | AutowireCapableBeanFactory.java| 789 | Another debug message

It would shows something like this:

DEBUG | DefaultBeanDefinitionDocumentReader.java| 86  | Loading bean definitions
DEBUG | AbstractAutowireCapableBeanFactory.java | 411 | Finished creating instance of bean 'MS-SQL'
DEBUG | DefaultSingletonBeanRegistry.java       | 213 | Creating shared instance of singleton bean 'MySQL'
DEBUG | AutowireCapableBeanFactory.java         | 383 | Creating instance of bean 'MySQL'
DEBUG | AutowireCapableBeanFactory.java         | 459 | |__ Eagerly caching bean 'MySQL' to allow for resolving potential circular references
DEBUG | AutowireCapableBeanFactory.java         | 789 |     |__ Another debug message

This is an example I just made up (VeryLongCamelCaseClassNamesNotMine). But I remember seeing such cleanly formatted log output and they were really much nicer than anything I had seen before and, in addition to being just plain nicer, they were also easier to read for they reproduced some of the logical organization of the code.

Yet I cannot find anymore what that library was.

I'm pretty sure it was fully compatible with log4j or sl4j.