Creation virtual machine failed via vijava

I wrote a java code with vijava to create a VM.

But vCenter throws error "The operation is not supported on the object."

How do I know which I make mistake which part? This error message says nothing.

I wrote following codes:

               si = new ServiceInstance(                   new URL("https://16.147.137.28/sdk"), "Administrator", "Passw0rd", true);              Folder rootFolder = si.getRootFolder();              InventoryNavigator rootNavi = new InventoryNavigator(rootFolder);              VirtualMachineConfigSpec vmConfig = new VirtualMachineConfigSpec();              vmConfig.setName("test");              vmConfig.setMemoryMB(500l);              vmConfig.setNumCPUs(4);              VirtualMachineFileInfo vmfi = new VirtualMachineFileInfo();              vmfi.setVmPathName("[datastore1]");              vmConfig.setFiles(vmfi);              VirtualDeviceConfigSpec vDiskConfigSpec = new VirtualDeviceConfigSpec();              vDiskConfigSpec.setOperation(VirtualDeviceConfigSpecOperation.add);              vDiskConfigSpec.setFileOperation(VirtualDeviceConfigSpecFileOperation.create);              VirtualDisk vDisk = new VirtualDisk();              vDisk.setCapacityInKB(1024 * 1024 * 16);              vDisk.setKey(0);              int ctrlKey = 0;              vDisk.setControllerKey(ctrlKey);              vDiskConfigSpec.setDevice(vDisk);              VirtualDiskFlatVer2BackingInfo vDiskFileBackInfo                = new VirtualDiskFlatVer2BackingInfo();              vDiskFileBackInfo.setThinProvisioned(true);              vDiskFileBackInfo.setFileName("[datastore1]");              VirtualSCSIController vScsiCtrl = new VirtualLsiLogicController();              vScsiCtrl.setBusNumber(0); vDisk.setUnitNumber(0);              vScsiCtrl.setKey(ctrlKey);              vScsiCtrl.setSharedBus(VirtualSCSISharing.noSharing);              vDiskFileBackInfo.setDiskMode(VirtualDiskMode.persistent.toString());              vDisk.setBacking(vDiskFileBackInfo);              VirtualDeviceConfigSpec vScsiConfigSpec = new VirtualDeviceConfigSpec();              vScsiConfigSpec.setOperation(VirtualDeviceConfigSpecOperation.add);              vScsiConfigSpec.setDevice(vScsiCtrl);              VirtualDeviceConfigSpec[] vDeviceConfigSpecs =                  new VirtualDeviceConfigSpec[]{ vDiskConfigSpec ,vScsiConfigSpec};              vmConfig.setDeviceChange(vDeviceConfigSpecs);              ResourcePool pool = (ResourcePool)rootNavi.searchManagedEntity("ResourcePool", "resource1");              Task task = pool.createChildVM_Task(vmConfig, null);              System.out.println(task.waitForTask());