log4j Log Levels and Their Relevance in PoolParty

TRACE

The TRACE Level designates finer-grained informational events than the DEBUG

Only used for dumps of data structures and stuff that produces a lot of logging output.

for example: Returned HTTP request body: <...>

DEBUG

The DEBUG Level designates fine-grained informational events that are most useful to debug an application.

More detailed checkpoints for tracing through a method/process, used for debugging.

for example: Found config file and reading it in

INFO

The INFO level designates informational messages that highlight the progress of the application at coarse-grained level.

Major checkpoints in the code, like invocation of a method or initialization of a process.

for example: Loading plugins at plugin directory XX

WARN

The WARN level designates potentially harmful situations.

A error that does not prevent the system from functioning as intended; the system can handle the error itself.

for example: No index found, a new one has to be created

ERROR

The ERROR level designates error events that might still allow the application to continue running.

Standard error level; a function does not work as intended, but it doesn't affect the entire system.

for example: Exception while evaluating a query

FATAL

The FATAL level designates very severe error events that will presumably lead the application to abort.

Very severe errors that crash the entire system or stop it from functioning.

for example: No connection to the triple store, essential components can't be loaded, etc.