| 1 | --- |
| 2 | id: jul |
| 3 | since: 2.4 |
| 4 | --- |
| 5 | |
| 6 | Here's an example of tracing a Java application which is using |
| 7 | **`java.util.logging`**: |
| 8 | |
| 9 | ~~~ java |
| 10 | import java.util.logging.Logger; |
| 11 | import org.lttng.ust.agent.LTTngAgent; |
| 12 | |
| 13 | public class Test |
| 14 | { |
| 15 | private static final int answer = 42; |
| 16 | |
| 17 | public static void main(String[] argv) throws Exception |
| 18 | { |
| 19 | // create a logger |
| 20 | Logger logger = Logger.getLogger("jello"); |
| 21 | |
| 22 | // call this as soon as possible (before logging) |
| 23 | LTTngAgent lttngAgent = LTTngAgent.getLTTngAgent(); |
| 24 | |
| 25 | // log at will! |
| 26 | logger.info("some info"); |
| 27 | logger.warning("some warning"); |
| 28 | Thread.sleep(500); |
| 29 | logger.finer("finer information; the answer is " + answer); |
| 30 | Thread.sleep(123); |
| 31 | logger.severe("error!"); |
| 32 | |
| 33 | // not mandatory, but cleaner |
| 34 | lttngAgent.dispose(); |
| 35 | } |
| 36 | } |
| 37 | ~~~ |
| 38 | |
| 39 | The LTTng-UST Java agent is packaged in a JAR file named |
| 40 | `liblttng-ust-agent.jar` It is typically located in |
| 41 | `/usr/lib/lttng/java`. To compile the snippet above |
| 42 | (saved as `Test.java`), do: |
| 43 | |
| 44 | <pre class="term"> |
| 45 | javac -cp /usr/lib/lttng/java/liblttng-ust-agent.jar Test.java |
| 46 | </pre> |
| 47 | |
| 48 | You can run the resulting compiled class like this: |
| 49 | |
| 50 | <pre class="term"> |
| 51 | java -cp /usr/lib/lttng/java/liblttng-ust-agent.jar:. Test |
| 52 | </pre> |
| 53 | |
| 54 | <div class="tip"> |
| 55 | <p> |
| 56 | <span class="t">Note:</span><a href="http://openjdk.java.net/" class="ext">OpenJDK</a> 7 |
| 57 | is used for development and continuous integration, thus this |
| 58 | version is directly supported. However, the LTTng-UST Java agent has |
| 59 | also been tested with OpenJDK 6. |
| 60 | </p> |
| 61 | </div> |