JDK24 removes CallersHolder for Java17SystemExitToggle

[fzakaria]

We bumped to Java24 and started to hit: "Failed to load Java 17 system exit override"

I no longer see this private static class in JDK24: https://github.com/openjdk/jdk24u/blob/master/src/java.base/share/classes/java/lang/System.java

Relevant line:
https://github.com/bazel-contrib/rules_jvm/blob/5ba4ba2b4e44eab9201c53cb5d87e87499f6cc28/java/src/com/github/bazel_contrib/contrib_rules_jvm/junit5/Java17SystemExitToggle.java#L17C60-L17C73

[fzakaria]

Looks like there is no solution now: https://inside.java/2024/12/11/quality-heads-up/

Some applications have used the Security Manager to intercept calls to the Java Platform API, such as blocking calls to System.exit. While this is not a security concern in most cases, interception remains helpful in debugging or managing application behavior. Below are a few alternative approaches that provide more reliability than the Security Manager’s interception mechanisms:

dynamic code rewriting - tools like bytecode manipulation agents can intercept and modify behavior without relying on the Security Manager.
static analysis - pre-deployment tools can identify and prevent undesirable API calls during the development cycle.

[fzakaria]

I think a java_agent attached to the runner would work:

(AI proposal)

/**
 * A Java Agent that intercepts calls to System.exit(int) and
 * instead throws a NoExitException.
 *
 * This agent uses ByteBuddy for bytecode instrumentation.
 * ByteBuddy dependencies must be available at agent loading time.
 */
public class ExitPreventionAgent {

    private static Instrumentation globalInstrumentation;

    /**
     * The premain method is the entry point for a Java agent.
     * It's called before the application's main method.
     *
     * @param agentArgs The arguments passed to the agent.
     * @param inst The Instrumentation instance provided by the JVM.
     */
    public static void premain(String agentArgs, Instrumentation inst) {
        globalInstrumentation = inst;
        System.out.println("ExitPreventionAgent: Premain method called. Installing transformer...");

        // Use ByteBuddy to intercept System.exit(int)
        new AgentBuilder.Default()
            // Only intercept the java.lang.System class
            .type(ElementMatchers.named("java.lang.System"))
            // Only intercept the exit(int) method
            .transform((builder, typeDescription, classLoader, module, protectionDomain) ->
                builder.method(ElementMatchers.named("exit").and(ElementMatchers.takesArguments(int.class)))
                       // Delegate calls to the interceptExit method in this agent
                       .intercept(MethodDelegation.to(ExitPreventionAgent.class))
            )
            .installOn(inst);

        System.out.println("ExitPreventionAgent: System.exit() method hooked successfully.");
    }

    /**
     * Interceptor method for System.exit(int).
     * When System.exit(status) is called, this method will be executed instead,
     * throwing a NoExitException.
     *
     * @param status The exit status code.
     */
    public static void interceptExit(int status) {
        System.err.println("ExitPreventionAgent: System.exit(" + status + ") intercepted! Throwing NoExitException.");
        throw new NoExitException(status);
    }

    // Optional: A way to reset the behavior, though with ByteBuddy's default
    // re-transformation, it's not straightforward to *un*-intercept a specific method
    // without re-transforming the class entirely or restarting the agent.
    // For simple test cases, typically you just load the agent for the test JVM
    // and let it do its job. If you need dynamic enable/disable, it's more complex.
    public static void reset() {
        // This is complex with ByteBuddy's standard usage.
        // It would require re-transforming the System class without the interceptor.
        // For simplicity in this example, we assume the agent is active for the JVM lifecycle.
        System.out.println("ExitPreventionAgent: Reset functionality not fully implemented for dynamic un-hooking.");
    }
}

[fzakaria]

@shs96c i think you landed the fix for this right via 84848ac