public static String random(final int count, final int start, final int end, final boolean letters, final boolean numbers, final char... chars) {
        return random(count, start, end, letters, numbers, chars, RANDOM);
    }
<p>Creates a random string based on a variety of options, using
default source of randomness.</p>

<p>This method has exactly the same semantics as
{@link #random(int, int, int, boolean, boolean, char[], Random)}, but
instead of using an externally supplied source of randomness, it uses
the internal static {@link Random} instance.</p>

@param count   the length of random string to create
@param start   the position in set of chars to start at
@param end     the position in set of chars to end before
@param letters only allow letters?
@param numbers only allow numbers?
@param chars   the set of chars to choose randoms from.
               If {@code null}, then it will use the set of all chars.
@return the random string
@throws ArrayIndexOutOfBoundsException if there are not
                                       {@code (end - start) + 1} characters in the set array.
android/android_framework/base/src/main/java/lang3/RandomStringUtils.java