src/org/kocakosm/pitaya/charset/UTF8.java
public static byte[] encode(String str, int off, int len)
	{
		return encode(str.substring(off, off + len));
	}
public static byte[] encode(String str, int off, int len)
	{
		return encode(str.substring(off, off + len));
	}
Returns the UTF-8 encoding of the specified character sequence.

@param str the input {@code String}.
@param off the start index, inclusive.
@param len the number of characters to encode.

@return the UTF-8 encoding of the specified characters.

@throws NullPointerException if {@code str} is {@code null}.
@throws IndexOutOfBoundsException if {@code off} or {@code len} is
negative or if {@code off + len} is greater than {@code str}'s
length.
@throws IllegalArgumentException if {@code str} can't be encoded into
UTF-8.