CODEWITHSUNDEEP
spring
oxygenan
oxygenan

Reputation: 1033

Logging in Spring framework -flow and configuration

When we run a sample main program which reads a applicationContext.xml with a single bean..

how does Spring do the logging..and how can one overwrite the default logging.

I didnt see any log4j.xml in the spring dependencies as well..

Regards

Upvotes: 1

Views: 1353

Answers (1)

JB Nizet
JB Nizet

Reputation: 692271

This is described in the documentation:

Logging is a very important dependency for Spring because a) it is the only mandatory external dependency, b) everyone likes to see some output from the tools they are using, and c) Spring integrates with lots of other tools all of which have also made a choice of logging dependency. One of the goals of an application developer is often to have unified logging configured in a central place for the whole application, including all external components. This is more difficult than it might have been since there are so many choices of logging framework.

The mandatory logging dependency in Spring is the Jakarta Commons Logging API (JCL). We compile against JCL and we also make JCL Log objects visible for classes that extend the Spring Framework. It's important to users that all versions of Spring use the same logging library: migration is easy because backwards compatibility is preserved even with applications that extend Spring. The way we do this is to make one of the modules in Spring depend explicitly on commons-logging (the canonical implementation of JCL), and then make all the other modules depend on that at compile time. If you are using Maven for example, and wondering where you picked up the dependency on commons-logging, then it is from Spring and specifically from the central module called spring-core.

The nice thing about commons-logging is that you don't need anything else to make your application work. It has a runtime discovery algorithm that looks for other logging frameworks in well known places on the classpath and uses one that it thinks is appropriate (or you can tell it which one if you need to). If nothing else is available you get pretty nice looking logs just from the JDK (java.util.logging or JUL for short). You should find that your Spring application works and logs happily to the console out of the box in most situations, and that's important.

(emphasis mine)

Follow several sections describing how to use various logging frameworks.

Upvotes: 2

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