# Logging

Logging is a very common feature for all applications. ES4X does not implement a logger, instead it just uses the logger from the JDK, also known as java util logging or JUL. Even the console object is linked to it, so you can disable console from logging at a specific level at runtime just by using configuration.

In order to customize the logging, create a file logging.properties with the configuration as you like. The default configuration is:

handlers=java.util.logging.ConsoleHandler
java.util.logging.ConsoleHandler.formatter=io.reactiverse.es4x.jul.ES4XFormatter
java.util.logging.ConsoleHandler.level=FINEST

.level=INFO
io.reactiverse.level=INFO
io.vertx.level=INFO
com.hazelcast.level=INFO
io.netty.util.internal.PlatformDependent.level=SEVERE

You can see that there is a custom formatter, this is to offer you a ANSI color logger. If the formatter is disabled all logs will be in plain text without ANSI codes.

TIP

To only log warning and errors at runtime, including from the console object, just level up the level on the console handler.

You can even ship the logs to other locations by adding more handlers.