Report: illegal reflective access operation

[deining]

SystemStubs 1.2.0

I'm testing a command line application based on the https://picocli.info framework.
While doing so, I encountered an illegal reflective access operation that I would like to report:

Minimum working example:

import org.junit.jupiter.api.Test;
import picocli.CommandLine;
import picocli.CommandLine.Command;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static uk.org.webcompere.systemstubs.SystemStubs.withEnvironmentVariable;

public class EnvTest {

    @Test
    void testEnvVar() throws Exception {
        @Command
        class MyApp {
        }
        String actual = withEnvironmentVariable("MYVAR", "some-value")
                .execute(() -> new CommandLine(new MyApp())
                        .getUsageMessage(CommandLine.Help.Ansi.OFF));

        String expected = "Usage: <main class>" + System.lineSeparator();
        assertEquals(expected, actual);
    }
}

When running the test, I'm getting:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by uk.org.webcompere.systemstubs.environment.EnvironmentVariables to field java.util.Collections$UnmodifiableMap.m
WARNING: Please consider reporting this to the maintainers of uk.org.webcompere.systemstubs.environment.EnvironmentVariables
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

Thanks for investigating!

[ashleyfrieze]

@deining thanks for the info... sadly, the fundamental way we can cheat Java into changing environment variables at runtime is by hacking into this map using reflection.

It's nothing to worry about, but it may mean that this library can no longer function in later versions of Java... At the moment, it functions up to JVM15.