copy pasted strip method from Apache Commons StringUtils - Character#isWhitespace replaced by Character#isSpaceChar (which is unicode aware)

StringUtils.java

import static org.apache.commons.lang3.StringUtils.isEmpty;

public class StringUtils {

    /**
     * unicode aware version of Apache Common's StringUtils#strip
     */
    public static String strip(String str) {
        if (isEmpty(str)) {
            return str;
        }
        str = stripStart(str, null);
        return stripEnd(str, null);
    }

    public static String stripStart(String str, String stripChars) {
        int strLen;
        if (str == null || (strLen = str.length()) == 0) {
            return str;
        }
        int start = 0;
        if (stripChars == null) {
            while ((start != strLen) && Character.isSpaceChar(str.charAt(start))) {
                start++;
            }
        } else if (stripChars.length() == 0) {
            return str;
        } else {
            while ((start != strLen) && (stripChars.indexOf(str.charAt(start)) != -1)) {
                start++;
            }
        }
        return str.substring(start);
    }

    public static String stripEnd(String str, String stripChars) {
        int end;
        if (str == null || (end = str.length()) == 0) {
            return str;
        }

        if (stripChars == null) {
            while ((end != 0) && Character.isSpaceChar(str.charAt(end - 1))) {
                end--;
            }
        } else if (stripChars.length() == 0) {
            return str;
        } else {
            while ((end != 0) && (stripChars.indexOf(str.charAt(end - 1)) != -1)) {
                end--;
            }
        }
        return str.substring(0, end);
    }

}

or you can use Google Guava

CharMatcher.WHITESPACE.trimFrom(source);