Reverse Words in a String

public static String reverseWords( String s ) {
    int ws = 0, we = 0;
    int len = s.length();
    StringBuilder sb = new StringBuilder();
    while( we < len ) {
        while( we < len && s.charAt(we) == ' ' ) ++we;
        ws = we;
        while( we < len && s.charAt(we) != ' ' ) ++we;
        for( int i = we-1; i >= ws; --i )
            sb.append( s.charAt(i) );
        sb.append( ' ' );
    }
    return new StringBuilder( sb.toString().trim() ).reverse().toString();
}