@BeforeClass
 public static void setUpBeforeClass() throws Exception {
   VMSettings.set(VMSettings.HEAP_SIZE, SEMI_SIZE * 2);
   VMSettings.set(VMSettings.GC_TYPE, VMConstants.GC_COPYING);
   VMMemoryManager.resetMemoryManager();
   VMMemoryManager.initializeMemoryManager();
 }
 @AfterClass
 public static void tearDownAfterClass() throws Exception {
   VMSettings.set(VMSettings.HEAP_SIZE, VMConstants.DEFAULT_HEAP_SIZE);
   VMSettings.set(VMSettings.GC_TYPE, VMConstants.GC_GENERATIONAL);
 }