BreakIterator与中文文本无法正常工作

我使用BreakIterator.getWordInstance将中文文本拆分为单词.这是我的例子

import java.text.BreakIterator;
import java.util.Locale;

public class Sample {
    public static void main(String[] args) {
        String stringToExamine = "I like to eat apples. ???????";

        //print each word in order
        BreakIterator boundary = BreakIterator.getWordInstance(new Locale("zh", "CN"));
        boundary.setText(stringToExamine);

        printEachForward(boundary, stringToExamine);
    }

    public static void printEachForward(BreakIterator boundary, String source) {
        int start = boundary.first();
        for (int end = boundary.next(); end != BreakIterator.DONE; start = end, end = boundary.next()) {
            System.out.println(start + ": " + source.substring(start, end));
        }
    }
}

0: I
1:  
2: like
6:  
7: to
9:  
10: eat
13:  
14: apples
20: .
21:  
22: ??????
28: ?

0 I
1  
2 like
6  
7 to
9  
10 eat
13  
14 apples
20 .
21  
22 ?
23 ??
25 ?
26 ??
28 ?