java为什么这种对泛型方法的重写适用于1.6,而不是1.7?
给定以下类,该类重写AbstractListModel中的getListeners方法:
import java.util.EventListener;
import javax.swing.AbstractListModel;
public class GenericBug extends AbstractListModel {
/**
* This is the method of interest
* This is the exact same method signature that is present in the base class
*/
@Override
public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
// do something useful here...
return super.getListeners(listenerType);
}
// Not important here
@Override
public int getSize() {
return 0;
}
@Override
public Object getElementAt(int index) {
return null;
}
}
这个类使用Oracle1.6JDK编译得很好。使用Oracle1.7JDK尝试完全相同的类时,我收到了编译错误,称存在名称冲突,但该方法没有被重写(但它是!!)
以下是我在使用JDK7时遇到的错误:
% /usr/java/jdk1.7.0/bin/javac GenericBug.java
GenericBug.java:10: error: name clash: <T#1>getListeners(Class<T#1>) in GenericBug and <T#2>getListeners(Class<T#2>) in AbstractListModel have the same erasure, yet neither overrides the other
public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
^
where T#1,T#2 are type-variables:
T#1 extends EventListener declared in method <T#1>getListeners(Class<T#1>)
T#2 extends EventListener declared in method <T#2>getListeners(Class<T#2>)
GenericBug.java:12: error: incompatible types
return super.getListeners(listenerType);
^
required: T[]
found: EventListener[]
where T is a type-variable:
T extends EventListener declared in method <T>getListeners(Class<T>)
GenericBug.java:9: error: method does not override or implement a method from a supertype
@Override
^
Note: GenericBug.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
3 errors
有人能给我解释一下发生了什么事吗?这是JDK1中的编译器错误吗。还是我遗漏了什么
共 (0) 个答案