HarmonyOS 鸿蒙Next 写了个定时器一直报错，求指导

报错信息如下：

Reason: NullPointerException

Selected stacktrace:

java.lang.NullPointerException: Attempt to invoke virtual method ‘void java.util.Timer.schedule(java.util.TimerTask, long, long)’ on a null object reference

at com.example.glancesapp.slice.CoreAbilitySlice.onStart(CoreAbilitySlice.java:37)
at ohos.aafwk.ability.AbilitySlice.start(AbilitySlice.java:3270)
at ohos.aafwk.ability.AbilitySliceScheduler.handleStartAbilitySlice(AbilitySliceScheduler.java:717)
at ohos.aafwk.ability.AbilitySliceManager.onAbilityStart(AbilitySliceManager.java:300)
at ohos.aafwk.ability.Ability.dispatchAbilityLifecycle(Ability.java:4579)
at ohos.aafwk.ability.Ability.start(Ability.java:3634)
at ohos.aafwk.ability.Ability.handleLifecycleTransaction(Ability.java:4751)
at ohos.aafwk.ability.Ability.scheduleAbilityLifecycle(Ability.java:1517)
at ohos.abilityshell.O00000o.O000000(AbilityShellDelegate.java:132)
at ohos.abilityshell.O00000O.O000000(AbilityShellActivityDelegate.java:340)
at ohos.abilityshell.AbilityShellActivity.onStart(AbilityShellActivity.java:67)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1447)
at android.app.Activity.performStart(Activity.java:8237)
at android.app.ActivityThread.handleStartActivity(ActivityThread.java:4084)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:235)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:215)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:187)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:105)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2613)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:219)
at android.app.ActivityThread.main(ActivityThread.java:8668)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1109)