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testngjavaagents

Load Java Agent In Tests Without JVM Arg

Each time I run a test from my IDE I get the error

java.lang.IllegalStateException: Missing the '-javaagent' JVM argument.

If I create a run config and add the jvm arg everything is fine. However, the next time I run a test on the fly that is not a pre-configured run config I get the error again.

I thought maybe I could use @BeforeClass to load the java agent dynamically. e.g.

@BeforeClass
public void loadAgent() {
    String nameOfRunningVM = ManagementFactory.getRuntimeMXBean().getName();
    String pid = nameOfRunningVM.substring(0, nameOfRunningVM.indexOf('@'));
    VirtualMachine vm = VirtualMachine.attach(pid);

    Class klass = JavaAgent.class;
    CodeSource codeSource = klass.getProtectionDomain().getCodeSource();
    String agentJar = codeSource.getLocation().getPath();

    vm.loadAgent(agentJar, "");
    vm.detach();
}

(maybe using a test listener might mean I don't copy and paste the code into every test class)

This works but it doesn't seem quite right.

Is there a way to do this without needing the pid?

Or is there a fundamentally better alternative to doing this?

Solution

  • For JDK8 the EA Agent Loader is a better choice and doesn't require the pid. However, it is discontinued for JDK9.

    Kotlin example where my agent happens to be called JavaAgent!

    AgentLoader.loadAgentClass(JavaAgent::class.java.name, "")