Escapes specified character with another specified character, similarly unescapes and splits a string

CharEscaper.java

import java.util.ArrayList;
import java.util.List;

public final class CharEscaper
{
	private final char escapeChar, escapeForEscapeChar;

	public CharEscaper(char escapeChar, char escapeForEscapeChar)
	{
		if (escapeChar == escapeForEscapeChar)
			throw new IllegalArgumentException();
		this.escapeChar = escapeChar;
		this.escapeForEscapeChar = escapeForEscapeChar;
	}

	public String escape(String str)
	{
		StringBuilder sb = new StringBuilder(str.length() + (str.length() / 14));
		for (int i = 0; i < str.length(); i++)
		{
			char c = str.charAt(i);
			if (c == escapeChar)
				sb.append(escapeForEscapeChar).append(escapeChar);
			else if (c == escapeForEscapeChar)
				sb.append(escapeForEscapeChar).append(escapeForEscapeChar);
			else
				sb.append(c);
		}
		return sb.toString();
	}

	public String unEscape(String escapedStr)
	{
		StringBuilder sb = new StringBuilder(escapedStr.length() - (escapedStr.length() / 14));
		for (int i = 0; i < escapedStr.length(); i++)
		{
			char c = escapedStr.charAt(i);
			if (c == escapeForEscapeChar)
			{
				i++;
				if (i < escapedStr.length() && escapedStr.charAt(i) == escapeForEscapeChar)
					sb.append(escapeForEscapeChar);
				else
					sb.append(escapedStr.charAt(i));
			}
			else
				sb.append(c);
		}
		return sb.toString();
	}

	/**
	 * @return un escaped strings obtained after splitting the provided
	 *         {@code escapedStr}
	 */
	public List<String> splitEscapedStr(String escapedStr)
	{
		List<String> parts = new ArrayList<String>();
		int startPos = 0;
		for (int i = 0; i < escapedStr.length(); i++)
		{
			char c = escapedStr.charAt(i);
			if (c == escapeForEscapeChar)
				i++;
			else if (c == escapeChar)
			{
				parts.add(unEscape(escapedStr.substring(startPos, i)));
				startPos = i + 1;
			}
		}
		parts.add(unEscape(escapedStr.substring(startPos, escapedStr.length())));
		return parts;
	}

	public static void main(String[] args) throws Throwable
	{
		String str = "a# b";
		CharEscaper strEscaper = new CharEscaper('#', '\\');

		String escapedStr = strEscaper.escape(str);
		System.out.println(escapedStr); // a\# b
		String unEscapedStr = strEscaper.unEscape(escapedStr);
		System.out.println(unEscapedStr); // a# b
		System.out.println(str.equals(unEscapedStr)); // true

		String strstr = escapedStr + "#" + "#" + escapedStr;
		System.out.println(strstr); // a\# b##a\# b
		List<String> parts = strEscaper.splitEscapedStr(strstr);
		System.out.println("No. of parts: " + parts.size()); // 3
		System.out.println(parts); // [a# b, , a# b]
		System.out.println(parts.get(2).equals(str)); // true
	}
}