问这个错误是什么意思，我如何解决它？

EN

W/art: Before Android 4.1, method double java.util.concurrent.ThreadLocalRandom.internalNextDouble(double, double) would have incorrectly overridden the package-private method in java.util.Random
   Before Android 4.1, method int java.util.concurrent.ThreadLocalRandom.internalNextInt(int, int) would have incorrectly overridden the package-private method in java.util.Random
   Before Android 4.1, method long java.util.concurrent.ThreadLocalRandom.internalNextLong(long, long) would have incorrectly overridden the package-private method in java.util.Random

Random r = new Random();
int i = r.nextInt(16 - 6) + 6;
long maxTimeInMilliseconds = (i * 1000);
startTimer(maxTimeInMilliseconds, 1000);