import java.lang.ref.Reference;
import java.lang.reflect.Field;

/**
 *
 */
public class ThreadLocalTest {

    private static ThreadLocal<String> threadLocal;

    public static void main(String[] args) throws Exception {
        System.out.println(System.getProperty("java.version"));

        threadLocal = new ThreadLocal<String>();
        threadLocal.set(">>> LEAK <<<");
//            threadLocal.remove();
        threadLocal = null;

        Runtime.getRuntime().gc();

        printThreadLocals(Thread.currentThread());
    }

    private static void printThreadLocals(Thread thread) throws IllegalAccessException, NoSuchFieldException {
        Object threadLocals = getFieldValue(thread, "threadLocals");
        Object[] table = (Object[]) getFieldValue(threadLocals, "table");
        for (Object entry : table) {
            if (entry != null) {
                Object threadLocal = getFieldValue(Reference.class, entry, "referent");
                Object threadLocalValue = getFieldValue(entry, "value");
                System.out.println(threadLocal + " = " + threadLocalValue);
            }
        }
    }

    private static Object getFieldValue(Object obj, String fieldName) throws IllegalAccessException, NoSuchFieldException {
        return getFieldValue(obj.getClass(), obj, fieldName);
    }

    private static Object getFieldValue(Class clazz, Object obj, String fieldName) throws IllegalAccessException, NoSuchFieldException {
        Field field = clazz.getDeclaredField(fieldName);
        field.setAccessible(true);
        return field.get(obj);
    }

}