Can we set a Thread Local variable from child class and access it in the parent class in Java?

I have an automation project with two Test classes(child classes) and a TestBase (parent class). In the TestBase I have a threadlocal attribute defined as below.

protected ThreadLocal<ITestContext> iTestContextThreadLocal = new ThreadLocal<>();

In each of the child class I'm setting an attribute called 'feature' into this ThreadLocal attribute. Sample Child class looks like below.

public class RestTests extends TestBase{

    @BeforeClass(alwaysRun = true)
    public void init(ITestContext iTestContext) {
        iTestContext.setAttribute("feature", "Sample - RestTests1");
        iTestContextThreadLocal.set(iTestContext);
        String feature = iTestContextThreadLocal.get().getAttribute("feature").toString();
    }

    @Test
    public void testScenario1(){
        //Automation Code
    }
}

In the TestBase I have an 'AfterMethod' inside which I try to access this value set in child class's before Method.

    @AfterMethod(alwaysRun = true)
    public void test() {
        try {
            ITestContext iTestContext = iTestContextThreadLocal.get();
            String feature = iTestContext.getAttribute("feature").toString();
            System.out.println("***** ThreadLocalAttribute: " + feature);

            //Rest of the code
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // Clean up the ThreadLocal variables after method execution
            iTestContextThreadLocal.remove();
        }
    }

The Issue I'm facing is - in parallel Test execution (in both classes and methods) feature set in one class is provided as the output. As an example if I set 'Sample - RestTests1' and 'Sample - RestTests2' as features in my child classes, when I try to access them in TestBase afterMethod using the below code, only one class's feature is given

iTestContext.getAttribute("feature").toString();

How to fix this and get feature set in each class via TestBase's AfterMethod ?

I have tried changing the order of annotations and trying out the solutions in the internet. But no fix is found yet.

Any help is highly appreciated. Thanks in Advance.

If you read, for example, this question on a similar topic, you'll see that there is a problem with TestNG's policy of creating only one instance per test class, and how to reset state if the test should be run in parallell.

I guess that in your case, you shouldn't have made the init method @BeforeClass, but rather @BeforeMethod, or perhaps @BeforeTest (don't remember the exact names).