Java开发网 - jdk1.5 hashmap put unchecked compile warnning?

Topic: jdk1.5 hashmap put unchecked compile warnning?

1.jdk1.5 hashmap put unchecked compile warnning?

Posted by: andersonmao
Posted on: 2005-05-27 15:23

I am using jdk1.5 to compile a java source file.[jdk-1_5_0_03-windows-i586-p.exe]
when do this:


Map map=new HashMap();
map.put("abc","def");

the compiler output warning like:

[javac] xxx.java 使用了未经检查或不安全的操作。
[javac] 注意：要了解详细信息，请使用 -Xlint:unchecked 重新编译。

I think this something about the generic.
When change to this:


Map<Object,Object> map=new HashMap<Object,Object>();
map.put("abc","def");

compiler OK.
Can anybody tell me it is a compiler error or other reason?
Thanks.