实现Comparable的Java警告

Question

我正在尝试在自定义对象的ArrayList上使用Collections.sort,但我收到警告,我无法弄清楚为什么

Warning: Type safety: Unchecked invocation 
sort(ArrayList<CharProfile>) of the generic method sort(List<T>) 
of type Collections

使用此代码:

ArrayList<CharProfile> charOccurrences = new ArrayList<CharProfile>();

...

Collections.sort(charOccurrences);

这是我的方法:

public class CharProfile implements Comparable {

...

@Override
public int compareTo(Object o) {

        if (this.probability == ((CharProfile)o).getProbability()) {
            return 0;
        }
        else if (this.probability > ((CharProfile)o).getProbability()) {
            return 1;
        }
        else {
            return -1;
        }
 }
}

Answer 1

Comparable应该用type来实现,这里Type是<CharProfile>.

public class CharProfile implements Comparable<CharProfile>{
       @Override
       public int compareTo(CharProfile cp) {
       ...
       }
}