Soft Assertion implementation using TestNG

BaseTest.java

import org.apache.commons.lang3.exception.ExceptionUtils;
import org.testng.IHookCallBack;
import org.testng.IHookable;
import org.testng.ITestResult;
import org.testng.Reporter;
import org.testng.asserts.SoftAssert;

public class BaseTest implements IHookable {
    String testName = null;

    private static final String SOFT_ASSERT = "softAssert";

    @Override
    public void run(IHookCallBack callBack, ITestResult testResult) {
        SoftAssert softAssert = new SoftAssert();
        testResult.setAttribute(SOFT_ASSERT, softAssert);
        callBack.runTestMethod(testResult);
        softAssert = getSoftAssert(testResult);
        if (!testResult.isSuccess()) {
            Throwable throwable = testResult.getThrowable();
            if (null != throwable) {
                if (null != throwable.getCause()) {
                    throwable = throwable.getCause();
                }
                softAssert.assertNull(throwable, ExceptionUtils.getStackTrace(throwable));
            }
        }
        softAssert.assertAll();
    }

    public static SoftAssert getSoftAssert() {
        return getSoftAssert(Reporter.getCurrentTestResult());
    }

    private static SoftAssert getSoftAssert(ITestResult result) {
        Object object = result.getAttribute(SOFT_ASSERT);
        if (object instanceof SoftAssert) {
            return (SoftAssert) object;
        }
        throw new IllegalStateException("Could not find a soft assertion object");
    }
}

I can't run because the test stuck at java.lang.IllegalStateException: Could not find a soft assertion object but i had
sa = BaseAssertTest.getSoftAssert();
sa.assertEquals( mapLayersPage.verifyCatchesCheckBox(),"true");
and i don't know String testName = null ? What is this variable

@tgthao - there are now better and easier ways to use soft assertions. Example: You can refer to assertj library for Java which gives you this capability out of the box - https://assertj.github.io/doc/
https://www.baeldung.com/introduction-to-assertj

TestNG also supports soft assertions now - https://www.javadoc.io/doc/org.testng/testng/6.8.8/org/testng/asserts/SoftAssert.html