+++ /dev/null
----
-id: java-application
----
-
-LTTng-UST provides a _logging_ back-end for Java applications using
-either
-<a href="http://docs.oracle.com/javase/7/docs/api/java/util/logging/Logger.html" class="ext"><code>java.util.logging</code></a>
-(JUL), or
-<a href="http://logging.apache.org/log4j/1.2/" class="ext">Apache log4j 1.2</a>.
-This back-end is called the _LTTng-UST Java agent_, and is responsible
-for communications with an LTTng session daemon.
-
-<div class="tip">
-<p>
- <span class="t">Note:</span>The latest stable version of LTTng
- does not support Log4j 2.
-</p>
-</div>
-
-From the user's point of view, once the LTTng-UST Java agent has been
-initialized, JUL and log4j loggers may be created and used as usual.
-The agent adds its own handler to the _root logger_, so that all
-loggers may generate LTTng events with no effort.
-
-Common JUL/log4j features are supported using the `lttng` tool
-(see [Controlling tracing](#doc-controlling-tracing)):
-
- * listing all logger names
- * enabling/disabling events per logger name
- * JUL/log4j log levels
-
-Here's an example using **`java.util.logging`**:
-
-~~~ java
-import java.util.logging.Logger;
-import org.lttng.ust.agent.LTTngAgent;
-
-public class Test
-{
- private static final int answer = 42;
-
- public static void main(String[] argv) throws Exception
- {
- // create a logger
- Logger logger = Logger.getLogger("jello");
-
- // call this as soon as possible (before logging)
- LTTngAgent lttngAgent = LTTngAgent.getLTTngAgent();
-
- // log at will!
- logger.info("some info");
- logger.warning("some warning");
- Thread.sleep(500);
- logger.finer("finer information; the answer is " + answer);
- Thread.sleep(123);
- logger.severe("error!");
-
- // not mandatory, but cleaner
- lttngAgent.dispose();
- }
-}
-~~~
-
-Here's the same example, this time using **log4j**:
-
-~~~ java
-import org.apache.log4j.Logger;
-import org.apache.log4j.BasicConfigurator;
-import org.lttng.ust.agent.LTTngAgent;
-
-public class Test
-{
- private static final int answer = 42;
-
- public static void main(String[] argv) throws Exception
- {
- // create and configure a logger
- Logger logger = Logger.getLogger(Test.class);
- BasicConfigurator.configure();
-
- // call this as soon as possible (before logging)
- LTTngAgent lttngAgent = LTTngAgent.getLTTngAgent();
-
- // log at will!
- logger.info("some info");
- logger.warn("some warning");
- Thread.sleep(500);
- logger.debug("debug information; the answer is " + answer);
- Thread.sleep(123);
- logger.error("error!");
- logger.fatal("fatal error!");
-
- // not mandatory, but cleaner
- lttngAgent.dispose();
- }
-}
-~~~
-
-The LTTng-UST Java agent classes are packaged in a JAR file named
-`liblttng-ust-agent.jar`. It is typically located in
-`/usr/lib/lttng/java`. To compile the snippets above
-(saved as `Test.java`), do:
-
-<pre class="term">
-javac -cp /usr/lib/lttng/java/liblttng-ust-agent.jar:$LOG4JCP Test.java
-</pre>
-
-where `$LOG4JCP` is the log4j 1.2 JAR file path, if you're using log4j.
-
-You can run the resulting compiled class like this:
-
-<pre class="term">
-java -cp /usr/lib/lttng/java/liblttng-ust-agent.jar:$LOG4JCP:. Test
-</pre>
-
-<div class="tip">
-<p>
- <span class="t">Note:</span><a href="http://openjdk.java.net/" class="ext">OpenJDK</a> 7
- is used for development and continuous integration, thus this
- version is directly supported. However, the LTTng-UST Java agent has
- also been tested with OpenJDK 6.
-</p>
-</div>
--- /dev/null
+---
+id: java-application
+---
+
+LTTng-UST provides a _logging_ back-end for Java applications using
+either
+<a href="http://docs.oracle.com/javase/7/docs/api/java/util/logging/Logger.html" class="ext"><code>java.util.logging</code></a>
+(JUL) or
+<a href="http://logging.apache.org/log4j/1.2/" class="ext">Apache log4j 1.2</a>.
+This back-end is called the _LTTng-UST Java agent_, and it is responsible
+for the communications with an LTTng session daemon.
+
+From the user's point of view, once the LTTng-UST Java agent has been
+initialized, JUL and log4j loggers may be created and used as usual.
+The agent adds its own handler to the _root logger_, so that all
+loggers may generate LTTng events with no effort.
+
+Common JUL/log4j features are supported using the `lttng` tool
+(see [Controlling tracing](#doc-controlling-tracing)):
+
+ * listing all logger names
+ * enabling/disabling events per logger name
+ * JUL/log4j log levels
--- /dev/null
+---
+id: jul
+---
+
+Here's an example of tracing a Java application which is using
+**`java.util.logging`**:
+
+~~~ java
+import java.util.logging.Logger;
+import org.lttng.ust.agent.LTTngAgent;
+
+public class Test
+{
+ private static final int answer = 42;
+
+ public static void main(String[] argv) throws Exception
+ {
+ // create a logger
+ Logger logger = Logger.getLogger("jello");
+
+ // call this as soon as possible (before logging)
+ LTTngAgent lttngAgent = LTTngAgent.getLTTngAgent();
+
+ // log at will!
+ logger.info("some info");
+ logger.warning("some warning");
+ Thread.sleep(500);
+ logger.finer("finer information; the answer is " + answer);
+ Thread.sleep(123);
+ logger.severe("error!");
+
+ // not mandatory, but cleaner
+ lttngAgent.dispose();
+ }
+}
+~~~
+
+The LTTng-UST Java agent is packaged in a JAR file named
+`liblttng-ust-agent.jar` It is typically located in
+`/usr/lib/lttng/java`. To compile the snippet above
+(saved as `Test.java`), do:
+
+<pre class="term">
+javac -cp /usr/lib/lttng/java/liblttng-ust-agent.jar Test.java
+</pre>
+
+You can run the resulting compiled class like this:
+
+<pre class="term">
+java -cp /usr/lib/lttng/java/liblttng-ust-agent.jar:. Test
+</pre>
+
+<div class="tip">
+<p>
+ <span class="t">Note:</span><a href="http://openjdk.java.net/" class="ext">OpenJDK</a> 7
+ is used for development and continuous integration, thus this
+ version is directly supported. However, the LTTng-UST Java agent has
+ also been tested with OpenJDK 6.
+</p>
+</div>
--- /dev/null
+---
+id: log4j
+since: 2.6
+---
+
+LTTng features an Apache log4j 1.2 agent, which means your existing
+Java applications using log4j 1.2 for logging can record events to
+LTTng traces with just a minor source code modification.
+
+<div class="tip">
+<p>
+ <span class="t">Note:</span>This version of LTTng does not
+ support Log4j 2.
+</p>
+</div>
+
+Here's an example:
+
+~~~ java
+import org.apache.log4j.Logger;
+import org.apache.log4j.BasicConfigurator;
+import org.lttng.ust.agent.LTTngAgent;
+
+public class Test
+{
+ private static final int answer = 42;
+
+ public static void main(String[] argv) throws Exception
+ {
+ // create and configure a logger
+ Logger logger = Logger.getLogger(Test.class);
+ BasicConfigurator.configure();
+
+ // call this as soon as possible (before logging)
+ LTTngAgent lttngAgent = LTTngAgent.getLTTngAgent();
+
+ // log at will!
+ logger.info("some info");
+ logger.warn("some warning");
+ Thread.sleep(500);
+ logger.debug("debug information; the answer is " + answer);
+ Thread.sleep(123);
+ logger.error("error!");
+ logger.fatal("fatal error!");
+
+ // not mandatory, but cleaner
+ lttngAgent.dispose();
+ }
+}
+~~~
+
+To compile the snippet above, do:
+
+<pre class="term">
+javac -cp /usr/lib/lttng/java/liblttng-ust-agent.jar:$LOG4JCP Test.java
+</pre>
+
+where `$LOG4JCP` is the log4j 1.2 JAR file path.
+
+You can run the resulting compiled class like this:
+
+<pre class="term">
+java -cp /usr/lib/lttng/java/liblttng-ust-agent.jar:$LOG4JCP:. Test
+</pre>
title: Dynamic linker tracing
- id: java-application
title: Java application
+ cats:
+ - id: jul
+ title: <code>java.util.logging</code>
+ - id: log4j
+ title: Apache log4j 1.2
- id: instrumenting-linux-kernel
title: Linux kernel
cats:
projects / lttng-docs.git / commitdiff
