5 LTTng-UST provides a _logging_ back-end for Java applications using
6 <a href="http://docs.oracle.com/javase/7/docs/api/java/util/logging/Logger.html" class="ext">Java Util Logging</a> (JUL). This back-end is called the _LTTng-UST JUL agent_ and is
7 responsible for communications with an LTTng session daemon.
9 From the user's point of view, once the LTTng-UST JUL agent has been
10 initialized, JUL loggers may be created and used as usual. The agent
11 adds its own handler to the _root logger_, so that all loggers may
12 generate LTTng events with no effort.
14 Common JUL features are supported using the `lttng` tool
15 (see [Controlling tracing](#doc-controlling-tracing)):
17 * listing all logger names
18 * enabling/disabling events per logger name
24 import java.util.logging.Logger;
25 import org.lttng.ust.jul.LTTngAgent;
29 public static void main(String[] argv) throws Exception
32 Logger logger = Logger.getLogger("jello");
34 // call this as soon as possible (before logging)
35 LTTngAgent lttngAgent = LTTngAgent.getLTTngAgent();
38 logger.info("some info");
39 logger.warning("some warning");
41 logger.finer("finer information...");
43 logger.severe("error!");
45 // not mandatory, but cleaner
51 The LTTng-UST JUL agent Java classes are packaged in a JAR file named
52 `liblttng-ust-jul.jar`. It is typically located in
53 `/usr/lib/lttng/java`. To compile the snippet above
54 (saved as `Test.java`), do:
57 javac -cp /usr/lib/lttng/java/liblttng-ust-jul.jar Test.java
60 You can run the resulting compiled class:
63 java -cp /usr/lib/lttng/java/liblttng-ust-jul.jar:. Test
68 <span class="t">Note:</span><a href="http://openjdk.java.net/" class="ext">OpenJDK</a> 7
69 is used for development and continuous integration, thus this
70 version is directly supported. However, the LTTng-UST JUL agent has
71 also been tested with OpenJDK 6.