[英]What is unchecked and unsafe operation here?
I have the following code: 我有以下代码:
private static final Set<String> allowedParameters;
static {
Set<String> tmpSet = new HashSet();
tmpSet.add("aaa");
allowedParameters = Collections.unmodifiableSet(tmpSet);
}
And it cause: 它导致:
Note: mygame/Game.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
And when I recompile with the suggested option I see a pointer (^) pointing at "new" in front of HashSet();
当我使用建议的选项重新编译时,我看到一个指针(^)指向
HashSet();
前面的“new” HashSet();
. 。
Does anybody know what is going on here? 有谁知道这里发生了什么?
Yes, you're creating a new HashSet without stating what class it should contain, and then asserting that it contains strings. 是的,你正在创建一个新的HashSet而不说明它应该包含哪个类,然后断言它包含字符串。 Change it to
将其更改为
Set<String> tmpSet = new HashSet<String>();
these messages occur when you are using classes that support the new J2SE 1.5 feature - generics. 当您使用支持新J2SE 1.5功能的类 - 泛型时,会出现这些消息。 You get them when you do not explicitly specify the type of the collection's content.
如果没有明确指定集合内容的类型,则可以获取它们。
For example: 例如:
List l = new ArrayList();
list.add("String");
list.add(55);
If you want to have a collection of a single data type you can get rid of the messages by: 如果您想拥有单一数据类型的集合,可以通过以下方式删除消息:
List<String> l = new ArrayList<String>();
list.add("String");
If you need to put multiple data types into once collection, you do: 如果您需要将多种数据类型放入一次集合中,您可以:
List<Object> l = new ArrayList<Object>();
list.add("String");
list.add(55);
If you add the -Xlint:unchecked parameter to the compiler, you get the specific details about the problem. 如果将-Xlint:unchecked参数添加到编译器,则会获得有关该问题的特定详细信息。
for more details refer here : http://forums.sun.com/thread.jspa?threadID=584311 有关详细信息,请参阅此处: http : //forums.sun.com/thread.jspa?threadID = 584311
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