Didn't find class "com.hyphenate.chatuidemo.DemoApplication"

ecplise 集成环信demo 报错：Unable to instantiate application com.hyphenate.chatuidemo.DemoApplication: java.lang.ClassNotFoundException: Didn't find class "com.hyphenate.chatuidemo.DemoApplication" on path: DexPathList[[zip file "/data/app/com.hyphenate.chatuidemo-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.hyphenate.chatuidemo-1, /system/lib]]