Java - random password generation

RandomPasswordGenerator.java

import java.security.SecureRandom;
import java.util.Random;

/**
 * @author softdev7
 */
public class RandomPasswordGenerator {

	private static final Random RANDOM = new SecureRandom();

	private static final String ALPHA_CAPS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	private static final String ALPHA = "abcdefghijklmnopqrstuvwxyz";
	private static final String NUM = "0123456789";
	private static final String SPL_CHARS = "!@#$%^&*_=+-/";
	private static final String ALL_CHARS = ALPHA_CAPS + ALPHA + NUM + SPL_CHARS;

	private static int[] randomIndexes(int len) {
		int[] indexes = new int[len];
		for (int i = 0; i < len; i++) {
			indexes[i] = i;
		}
		for (int i = len - 1, j, t; i > 0; i--) {
			j = RANDOM.nextInt(i);
			t = indexes[j];
			indexes[j] = indexes[i];
			indexes[i] = t;
		}
		return indexes;
	}

	public static String generatePswd(int minLen, int maxLen, int noOfCAPSAlpha,
									  int noOfDigits, int noOfSplChars) {
		if (minLen > maxLen) {
			throw new IllegalArgumentException("Min. Length > Max. Length!");
		}
		if ((noOfCAPSAlpha + noOfDigits + noOfSplChars) > minLen) {
			throw new IllegalArgumentException
					("Min. Length should be atleast sum of (CAPS, DIGITS, SPL CHARS) Length!");
		}

		int len = RANDOM.nextInt(maxLen - minLen + 1) + minLen;
		int[] indexes = randomIndexes(len);
		char[] pswd = new char[len];

		int j = 0;
		for (; j < noOfCAPSAlpha; j++) {
			pswd[indexes[j]] = ALPHA_CAPS.charAt(RANDOM.nextInt(ALPHA_CAPS.length()));
		}
		for (; j < (noOfCAPSAlpha + noOfDigits); j++) {
			pswd[indexes[j]] = NUM.charAt(RANDOM.nextInt(NUM.length()));
		}
		for (; j < (noOfCAPSAlpha + noOfDigits + noOfSplChars); j++) {
			pswd[indexes[j]] = SPL_CHARS.charAt(RANDOM.nextInt(SPL_CHARS.length()));
		}
		for (; j < len; j++) {
			pswd[indexes[j]] = ALPHA.charAt(RANDOM.nextInt(ALPHA.length()));
		}
		return new String(pswd);
	}
}