1. Agent is available for JDK 1.6 - 12.
2. Find agent folder in SkyWalking release package
3. Set agent.service_name in config/agent.config. Could be any String in English.
4. Set collector.backend_service in config/agent.config. Default point to 127.0.0.1:11800, only works for local backend.
5. Add -javaagent:/path/to/skywalking-package/agent/skywalking-agent.jar to JVM argument. And make sure to add it before the -jar argument.

The agent release dist is included in Apache official release. New agent package looks like this.

+-- agent
    +-- activations
         apm-toolkit-log4j-1.x-activation.jar
         apm-toolkit-log4j-2.x-activation.jar
         apm-toolkit-logback-1.x-activation.jar
         ...
    +-- config
         agent.config  
    +-- plugins
         apm-dubbo-plugin.jar
         apm-feign-default-http-9.x.jar
         apm-httpClient-4.x-plugin.jar
         .....
    +-- optional-plugins
         apm-gson-2.x-plugin.jar
         .....
    +-- bootstrap-plugins
         jdk-http-plugin.jar
         .....
    +-- logs
    skywalking-agent.jar

• Start your application.

SkyWalking agent has supported various middlewares, frameworks and libraries. Read supported list to get them and supported version. If the plugin is in Optional² catalog, go to optional plugins section to learn how to active it.

• All plugins are in /plugins folder. The plugin jar is active when it is in there. Remove the plugin jar, it disabled.
• The default logging output folder is /logs.

• Linux Tomcat 7, Tomcat 8
  Change the first line of tomcat/bin/catalina.sh.

CATALINA_OPTS="$CATALINA_OPTS -javaagent:/path/to/skywalking-agent/skywalking-agent.jar"; export CATALINA_OPTS

• Windows Tomcat 7, Tomcat 8
  Change the first line of tomcat/bin/catalina.bat.

set "CATALINA_OPTS=-javaagent:/path/to/skywalking-agent/skywalking-agent.jar"

• JAR file
  Add -javaagent argument to command line in which you start your app. eg:

java -javaagent:/path/to/skywalking-agent/skywalking-agent.jar -jar yourApp.jar

• Jetty
  Modify jetty.sh, add -javaagent argument to command line in which you start your app. eg:

export JAVA_OPTIONS="${JAVA_OPTIONS} -javaagent:/path/to/skywalking-agent/skywalking-agent.jar"

This is the properties list supported in agent/config/agent.config.

Java agent plugins are all pluggable. Optional plugins could be provided in optional-plugins folder under agent or 3rd party repositories. For using these plugins, you need to put the target plugin jar file into /plugins.

Now, we have the following known optional plugins.

• Plugin of tracing Spring annotation beans
• Plugin of tracing Oracle and Resin
• Filter traces through specified endpoint name patterns
• Plugin of Gson serialization lib in optional plugin folder.
• Plugin of Lettuce 5.x(JRE 8+) in optional plugin folder. Agent is compatible in JDK 1.6+, this plugin could be used in JRE 8+, by matching the lib requirement.
• Plugin of Zookeeper 3.4.x in optional plugin folder. The reason of being optional plugin is, many business irrelevant traces are generated, which cause extra payload to agents and backends. At the same time, those traces may be just heartbeat(s).
• Customize enhance Trace methods based on description files, rather than write plugin or change source codes.
• Plugin of Spring Cloud Gateway 2.1.x in optional plugin folder. Please only active this plugin when you install agent in Spring Gateway. spring-cloud-gateway-2.x-plugin and spring-webflux-5.x-plugin are both required.
• Plugin of Play Framework 2.6+ (JDK 1.8 required & Scala 2.12/2.13) in optional plugin folder. Please only active this plugin when you install agent in Play Framework.
• Plugin of Spring Transaction in optional plugin folder. The reason of being optional plugin is, many local span are generated, which also spend more CPU, memory and network.
• Plugin of Spring Webflux 5.x in the optional plugin folder. Because the plugin requires JDK 1.8+.

All bootstrap plugins are optional, due to unexpected risk. Bootstrap plugins are provided in bootstrap-plugins folder. For using these plugins, you need to put the target plugin jar file into /plugins.

Now, we have the following known bootstrap plugins.

• Plugin of JDK HttpURLConnection. Agent is compatible with JDK 1.6+
• Plugin of JDK Callable and Runnable. Agent is compatible with JDK 1.6+

• Set the settings through system properties for config file override. Read setting override.
• Use gRPC TLS to link backend. See open TLS
• Monitor a big cluster by different SkyWalking services. Use Namespace to isolate the context propagation.
• Set client token if backend open token authentication.
• Application Toolkit, are a collection of libraries, provided by SkyWalking APM. Using them, you have a bridge between your application and SkyWalking APM agent.
  • If you want to use OpenTracing Java APIs, try SkyWalking OpenTracing compatible tracer. More details you could find at http://opentracing.io
  • If you want to print trace context(e.g. traceId) in your logs, choose the log frameworks, log4j, log4j2, logback
  • If you want to use annotations or SkyWalking native APIs to read context, try SkyWalking manual APIs
  • If you want to continue traces across thread manually, use across thread solution APIs.
• If you want to specify the path of your agent.config file. Read set config file through system properties

SkyWalking java agent supports plugin to extend the supported list. Please follow our Plugin Development Guide.

If some RPC framework endpoints(server side) could include parameter, please read Operation Name Group Rule, and consider to add this feature.

If you are interested in plugin compatible tests or agent performance, see the following reports.

• Plugin Test in every Pull Request
• Java Agent Performance Test