contents/using-lttng/instrumenting/java-application/intro.md

   1 ---
   2 id: java-application
   3 since: 2.4
   4 ---
   5
   6 LTTng-UST provides a _logging_ back-end for Java applications using
   7 either
   8 <a href="http://docs.oracle.com/javase/7/docs/api/java/util/logging/Logger.html" class="ext"><code>java.util.logging</code></a>
   9 (JUL) or
  10 <a href="http://logging.apache.org/log4j/1.2/" class="ext">Apache log4j 1.2</a>.
  11 This back-end is called the _LTTng-UST Java agent_, and it is responsible
  12 for the communications with an LTTng session daemon.
  13
  14 From the user's point of view, once the LTTng-UST Java agent has been
  15 initialized, JUL and log4j loggers may be created and used as usual.
  16 The agent adds its own handler to the _root logger_, so that all
  17 loggers may generate LTTng events with no effort.
  18
  19 Common JUL/log4j features are supported using the `lttng` tool
  20 (see [Controlling tracing](#doc-controlling-tracing)):
  21
  22   * listing all logger names
  23   * enabling/disabling events per logger name
  24   * JUL/log4j log levels