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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"null object reference when creating ViewModelFactory class","articleBody":"Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'androidx.lifecycle.LiveData com.lemon.sleepsamplejava.data.db.SleepSegmentEventDao.getAll()' on a null object reference\r\n        at com.lemon.sleepsamplejava.data.SleepRepository.\u003cinit\u003e(SleepRepository.java:21)\r\n        at com.lemon.sleepsamplejava.MainApplication.getRepository(MainApplication.java:23)\r\n        at com.lemon.sleepsamplejava.MainActivity.onCreate(MainActivity.java:60)\r\n\r\nerror occures in MainActivity at this line of code:\r\n\r\n`mainViewModel = new ViewModelProvider(this, new MainViewModelFactory(mainApplication.getRepository())).get(MainViewModel.class);`","author":{"url":"https://github.com/vipozdn","@type":"Person","name":"vipozdn"},"datePublished":"2021-04-22T16:56:44.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/1/SleepSampleJava/issues/1"}