Getting the position and length of the longest consecutive repeating character in a form of "position,length" of the sample passed to the constructor.

StringUtility.java

package com.lazlondon.interview;

/**
 * Created by Laz on 10/09/2016.
 */

import net.jcip.annotations.ThreadSafe;

/**
 * Utility class for String manipulation.
 */
@ThreadSafe
public class StringUtility {
    private final String sample;

    public StringUtility(String sample) {
        this.sample = sample;
    }

    /**
     * Getting the position and length of the longest consecutive repeating character in a form of "position,length" of the sample passed to the constructor.
     *
     * @return -1 if the sample is null or empty string, otherwise it returns the position and length of the longest consecutive repeating character.
     */
    public String getPosLenOfLCRC() {
        if (isEmptySample()) {
            return "-1";
        }
        return getPosLenOfLCRCWhenThereIsSample();
    }

    private boolean isEmptySample() {
        return (sample == null) || (sample.length() == 0);
    }

    private String getPosLenOfLCRCWhenThereIsSample() {
        LCRC resultLCRC = new LCRC(0, 1);
        LCRC actualLCRC = new LCRC(1, 0);

        while (actualLCRC.position < sample.length()) {
            actualLCRC.length = getTheNumberOfConsecutiveRepeatationOfTheCharacterAtPosition(actualLCRC.position);
            if (actualLCRC.length > resultLCRC.length) {
                resultLCRC.setBy(actualLCRC);
            }
            actualLCRC.position += actualLCRC.length;
        }
        return resultLCRC.position + "," + resultLCRC.length;
    }

    /**
     * The representation of the longest consecutive repeating character.
     */
    private class LCRC {
        private int position, length;

        public LCRC(int position, int length) {
            this.position = position;
            this.length = length;
        }

        public void setBy(LCRC actualLCRC) {
            position = actualLCRC.position;
            length = actualLCRC.length;
        }
    }

    private int getTheNumberOfConsecutiveRepeatationOfTheCharacterAtPosition(int i) {
        int j = i;
        while ((++j < sample.length()) && (sample.charAt(j) == sample.charAt(i))) ;
        return j - i;
    }
}

StringUtilityTest.java

package com.lazlondon.interview;

import org.junit.Test;

import static org.junit.Assert.assertEquals;

/**
 * Created by Laz on 10/09/2016.
 */
public class StringUtilityTest {

    void assertLongestConsecutiveRepeatingCharacter(String expected, String sample) {
        StringUtility stringUtility = new StringUtility(sample);
        assertEquals(expected, stringUtility.getPosLenOfLCRC());
    }

    @Test
    public void testEmptyString() {
        assertLongestConsecutiveRepeatingCharacter("-1", "");
    }

    @Test
    public void testNull() {
        assertLongestConsecutiveRepeatingCharacter("-1", null);
    }

    @Test
    public void testOneCharacterLength() {
        assertLongestConsecutiveRepeatingCharacter("0,1", "a");
    }

    @Test
    public void test2CharacterLength() {
        assertLongestConsecutiveRepeatingCharacter("0,2", "aa");
    }

    @Test
    public void test2DifferentCharacters() {
        assertLongestConsecutiveRepeatingCharacter("0,1", "ab");
    }

    @Test
    public void testABAA() {
        assertLongestConsecutiveRepeatingCharacter("2,2", "abaa");
    }

    @Test
    public void testAABBB() {
        assertLongestConsecutiveRepeatingCharacter("2,3", "aabbb");
    }

}

Please feel free to do a code review. Any ideas how to make it more clean? (especially in the while loop)