可以将一个泛型参数绑定为：
public< T super Object> void someMethod（T t）;是否有这样一个绑定的有效用法？
解决方案根据JLS docs.oracle/javase/specs/jls/se7/html/jls-4.html#jls-4.4 类型参数（< T
TypeParameter： TypeVariable TypeBound * TypeBound： extends TypeVariable extends ClassOrInterfaceType AdditionalBoundList * AdditionalBoundList： AdditionalBound AdditionalBoundList AdditionalBound AdditionalBound：&接口类型* =可选
TypeBound ，仅指定 extends 的用法。 不幸的是，未指定使用 super 的下限类型参数。下限仅在通配符用法中指定（ JLS＃4.5.1 ）
好的问题，让我在JLS中挖掘，我不知道为什么没有实现在java中，它只是没有指定。
It is possible to code a generic parameter bound as:
public <T super Object> void someMethod(T t);Is there a valid usage of such a bound?
解决方案According to the JLS docs.oracle/javase/specs/jls/se7/html/jls-4.html#jls-4.4 a type parameter (The < T extends Object > term) consists out of:
TypeParameter: TypeVariable TypeBound* TypeBound: extends TypeVariable extends ClassOrInterfaceType AdditionalBoundList* AdditionalBoundList: AdditionalBound AdditionalBoundList AdditionalBound AdditionalBound: & InterfaceType* = optional
You see the TypeBound, there is only the usage of extends specified. Unfortunately, a lower bound type parameter, using super, is not specified. A lower bound is only specified in the wildcard usage (JLS#4.5.1)
Good question, that got me digging in the JLS, and I don't know why this not implemented in java, it is just not specified.