以下两个签名是否相同？
public static <T> void work(Class<T> type,T instance);
和
public static <T,S extends T> void work(Class<T> type,S instance);
不,这两个签名是不一样的.从
Java Language Spec,Chapter 8：
Two methods have the same signature if they have the same name and argument types.
Two method or constructor declarations M and N have the same argument types if all of the following conditions hold:
- They have the same number of formal parameters (possibly zero)
- They have the same number of type parameters (possibly zero)
…
由于您的两种方法不共享相同数量的类型参数,因此签名不一样.
在使用隐式类型参数调用方法的实际情况下,它们可能被视为可互换的.但是这只是在源代码级别,从不在二进制级别.换句话说,如果您在类Foo中有一个类型参数版本的work(),并且它由类Bar中的方法调用,然后切换到work()的两个类型参数版本并重新编译唔,你还需要重新编译吧.
编辑
@onepotato问：
If they don’t have the same signatures,then why when I copy and paste them in one class Eclipse tell me that they have the same method signature?
两个签名之间存在差异,两个签名相冲突(为“超越等效”).两个签名冲突,如果一个是另一个的子签名.稍后将在同一节中解释：
Two method signatures m1 and m2 are override-equivalent iff either m1 is a subsignature of m2 or m2 is a subsignature of m1.
It is a compile-time error to declare two methods with override-equivalent signatures in a class.
The signature of a method m1 is a subsignature of the signature of a method m2 if either:
- m2 has the same signature as m1,or
- the signature of m1 is the same as the erasure (§4.6) of the signature of m2.
