toUpperCase

public String toUpperCase(Locale locale) {
	if (locale == null) {
	    throw new NullPointerException();
        }

        int     firstLower;

	/* Now check if there are any characters that need to be changed. */
	scan: {
	    for (firstLower = 0 ; firstLower < count; ) {
		int c = (int)value[offset+firstLower];
		int srcCount;
		if ((c >= Character.MIN_HIGH_SURROGATE) &&
		    (c <= Character.MAX_HIGH_SURROGATE)) {
		    c = codePointAt(firstLower);
		    srcCount = Character.charCount(c);
		} else {
		    srcCount = 1;
		}
		int upperCaseChar = Character.toUpperCaseEx(c);
		if ((upperCaseChar == Character.ERROR) ||
		    (c != upperCaseChar)) {
		    break scan;
		}
		firstLower += srcCount;
	    }
	    return this;
	}

        char[]  result       = new char[count]; /* may grow */
	int     resultOffset = 0;  /* result may grow, so i+resultOffset
				    * is the write location in result */

	/* Just copy the first few upperCase characters. */
	System.arraycopy(value, offset, result, 0, firstLower);

	String lang = locale.getLanguage();
	boolean localeDependent =
            (lang == "tr" || lang == "az" || lang == "lt");
        char[] upperCharArray;
        int upperChar;
        int srcChar;
        int srcCount;
        for (int i = firstLower; i < count; i += srcCount) {
	    srcChar = (int)value[offset+i];
	    if ((char)srcChar >= Character.MIN_HIGH_SURROGATE &&
	        (char)srcChar <= Character.MAX_HIGH_SURROGATE) {
		srcChar = codePointAt(i);
		srcCount = Character.charCount(srcChar);
	    } else {
	        srcCount = 1;
	    }
            if (localeDependent) {
                upperChar = ConditionalSpecialCasing.toUpperCaseEx(this, i, locale);
            } else {
                upperChar = Character.toUpperCaseEx(srcChar);
            }
            if ((upperChar == Character.ERROR) ||
                (upperChar >= Character.MIN_SUPPLEMENTARY_CODE_POINT)) {
                if (upperChar == Character.ERROR) {
                    if (localeDependent) {
                        upperCharArray =
                            ConditionalSpecialCasing.toUpperCaseCharArray(this, i, locale);
                    } else {
                        upperCharArray = Character.toUpperCaseCharArray(srcChar);
                    }
                } else if (srcCount == 2) {
		    resultOffset += Character.toChars(upperChar, result, i + resultOffset) - srcCount;
		    continue;
                } else {
                    upperCharArray = Character.toChars(upperChar);
		}

                /* Grow result if needed */
                int mapLen = upperCharArray.length;
		if (mapLen > srcCount) {
                    char[] result2 = new char[result.length + mapLen - srcCount];
                    System.arraycopy(result, 0, result2, 0,
                        i + resultOffset);
                    result = result2;
		}
                for (int x=0; x<mapLen; ++x) {
                    result[i+resultOffset+x] = upperCharArray[x];
                }
                resultOffset += (mapLen - srcCount);
            } else {
                result[i+resultOffset] = (char)upperChar;
            }
        }
        return new String(0, count+resultOffset, result);
    }