Java agent problem on J9.

Foo.java

public class Foo {

    public static void main(String[] args) throws UnmodifiableClassException, InterruptedException {
        
        // jar: https://bintray.com/raphw/maven/download_file?file_path=net%2Fbytebuddy%2Fbyte-buddy-agent%2F1.4.26%2Fbyte-buddy-agent-1.4.26.jar
        Instrumentation instrumentation = ByteBuddyAgent.install();
        
        System.out.println(instrumentation.isRedefineClassesSupported());
        System.out.println(instrumentation.isRetransformClassesSupported());
        
        // Successfully attaches agent to running process but also prints:
        // *** java.lang.instrument ASSERTION FAILED ***: "jvmtierror == JVMTI_ERROR_NOT_AVAILABLE" at JPLISAgent.c line: 1009
       
        // Prints 'false, false' even though manifest headers are specified correctly
        // However: prints 'true, true' if another transformation-capable Javaagent was attached at startup.
        // Its the easiest to attach the debugger to the process which implies such an agent.
        // This also avoids the assertion.
    
        // java version "1.8.0"
        // Java(TM) SE Runtime Environment (build pxa6480sr3fp11-20160817_02(SR3 FP11))
        // IBM J9 VM (build 2.8, JRE 1.8.0 Linux amd64-64 Compressed References 20160816_315341 (JIT enabled, AOT enabled)
        // J9VM - R28_20160816_1459_B315341
        // JIT  - tr.r14.java.green_20160726_121883
        // GC   - R28_20160816_1459_B315341_CMPRSS
        // J9CL - 20160816_315341)
        // JCL - 20160816_01 based on Oracle jdk8u101-b13
        
        // Googling this issue shows a dozen similar issues.
    }
}

J9 doesn't support redefinition / retransformation when using late attach. Those capabilities need to be requested at startup.