Java程序在eclipse中编译而不是netbeans？

Question

In eclipse this line of code compiles and the program runs fine.

SimpleAdapter adapter = new SimpleAdapter(getApplicationContext(), (List<? extends Map<String, ?>>) data, R.layout.message_list_item, from, to);

It gives the warning:

unchecked cast from ArrayList<Map> to List<? extends Map<String, ?>>

In netbeans however:

Incompatible types: ArrayList<Map> cannot be converted to List<? extends Map<String, ?>>

And then the runtime error:

error: inconvertible types
            SimpleAdapter adapter = new SimpleAdapter(getApplicationContext(), (List<? extends Map<String, ?>>) data, R.layout.message_list_item, from, to);
required: List<? extends Map<String,?>>
found:    ArrayList<Map>

Can someone please explain this difference in behaviour to me? Thanks.

Answer 1

检查两个平台并确保在两个IDE中都运行相同的JDK版本，这很可能是问题所在。

Answer 2

Eclipse has it's own Java compiler while Netbeans uses the one from your JDK. They are compatible and both produce valid code but for some obscure features (especially in the area of generics), they aren't 100% compatible. Most of the time, the Eclipse compiler will be able to handle more complex cases.

Try to install Java 7 and use that for Netbeans. Oracle has fixed some bugs in the compiler.

EDIT After looking at the question again, I see a problem: You're mixing generic and raw types: You try to cast Map to Map<String,?> .

Try to use a generic type when you declare data instead of ArrayList<Map> . If that doesn't work, then you can use this workaround:

    @SuppressWarnings( { "unchecked", "rawtypes" } )
    java.util.List<? extends Map<String, ?>> tmp = (java.util.List<? extends Map<String, ?>>)((List) data);

This little trick strips all generics information from the right hand side before the compiler has a chance to use it against you.