QOS.CH Sarl (Switzerland)
QOS.ch Sarl (Switzerland) is a software design and development company based in Vouvry, Switzerland. Our company has experience building mission-critical enterprise software using the Java language.
Professional Support
Although the quality of support for various open source projects can be good, most are operated on a best-effort basis. If you require authoritative responses and guaranteed response times, then please read on.
As the founding contributors of several open source projects, namely log4j 1.x, reload4j, slf4j and logback, we offer professional support for these projects.
The base support package entails guaranteed response times. Just as importantly, it includes a review of your logging practices. Such reviews often result in considerable savings in reduced infrastructure costs. We also offer custom development services.
For more information about our support package please contact us. We will be happy to provide further details and discuss your specific needs.
Donations and sponsorships
You can also support SLF4J/logback projects via donations and sponsorship. We thank our current supporters and sponsors for their continued contributions.
Contact
| Email: | sales(at)qos.ch |
| Postal Address: | QOS.ch Sàrl rue Grand-Rue 32 CH-1896 Vouvry (VS) Switzerland |
Prevalence of logging frameworks
Regarding the log4shell vulnerability, the prevalence of various java logging libraries puts things into perspective. Here are the relevant figures as found in mvnrepository site on 2025-10-20.
| Project | Category | group:artifact | usageCount | percentage |
|---|---|---|---|---|
| SLF4J | API | org.slf4j:slf4j-api | 78,695 | 70% |
| Commons-logging | API | commons-logging:commons-logging | 13,432 | 12% |
| SLF4J | API | org.slf4j:jcl-over-slf4j | 10,196 | 9% |
| LOG4J 2.x | API | org.apache.logging.log4j:log4j-api | 10,854 | 10% |
| Total | API | - | 113,177 | 100% |
| Project | Category | group:artifact | usageCount | percentage |
|---|---|---|---|---|
| LOGBACK | implementation | ch.qos.logback:logback-classic | 31,580 | 49% |
| LOG4J 1.x | implementation | log4j:log4j | 19,855 | 31% |
| LOG4J 2.x | implementation | org.apache.logging.log4j:log4j-core | 13,172 | 20% |
| Total | implementaion | - | 64,607 | 100% |
Notwithstanding its 49% prevalence overall (in the implementation category), no attacks have been reported against logback that we are aware of.