在json解析时出现Didn't find class

java.lang.ClassNotFoundException: Didn't find class "java.util.ConcurrentNavigableMap" on path: DexPathList[[zip file "/data/app/com.jxx.android.elearning-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.jxx.android.elearning-1, /vendor/lib, /system/lib]] json解析时出现这个异常是怎么回事？