illustrate
1. The lower bound wildcard restricts unknown types to specific types or supertypes.
2. The lower bound wildcard uses the wildcard character ('?').
Indicates that it is followed by the super keyword, and then its lower limit <? super A > .
3. The class instantiated under the wildcard must be the current class or a superclass of the current class.
When storing data, the data type can only be the current class or a superclass of the current class.
Example
public static void addNumbers(List<? super Integer> list) {
for (int i = 1; i <= 10; i++) {
list.add(i);
}
}The above is the usage of Java lower bound wildcard, I hope it will be helpful to everyone.