public static ExecuteEnv getInstance() {
        return INSTANCE;
    }
@Test
    public void testGetInstance() {
        Set<Thread> tds = new HashSet<Thread>();
        for (int i = 0; i < THREAD_MAX_NUM; i++) {
            Thread td = new Thread(new MyTest(i, oids));
            tds.add(td);
            td.start();
        }

        for (Thread td : tds) {
            try {
                td.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        for (int i = 1; i < THREAD_MAX_NUM; i++) {
            Assert.assertEquals(oids[i - 1], oids[i]);
        }
    }