List<子类>传入someMethod(List<父类> alist)问题

List<子类>是不能传进someMethod(List<父类> alist)的，List<子类>并不是List<父类>的子类，可以利用范型改造方法来解决此问题。

详细示例：

public interface IParam {
    String getAName();
}

public class SuperClass {
}

public class SubClass extends SuperClass implements IParam{
    @Override
    public String getAName() {
       return "a name of sub class";
    }
}

public class TestParam {    
    public void tryInheritance(SuperClass superClass){
        System.out.println("tryInheritance");
    }
    public void tryInterface(IParam iParam) {
        System.out.println("tryInterface");
    }
    
    public void tryInheritanceList(List<SuperClass> superClassList){
        System.out.println("tryInheritance list");
    }
    public void tryInterfaceList(List<IParam> iParam) {
        System.out.println("tryInterface list");
    }
    
    public <T extends IParam> void tryGeneric(List<T> listT){
        System.out.println("tryGeneric");
    }
    
    
    public static void main(String[] args){
        TestParam t = new TestParam();
        SuperClass superC = new SuperClass();
        SubClass subC = new SubClass();
        List<SuperClass> superList = new ArrayList<SuperClass>();
        List<SubClass> subList = new ArrayList<SubClass>();
        
        t.tryInheritance(subC); // 参数类型SuperClass，传入子类ok
        t.tryInterface(subC);   // 参数类型IParam，传入实现类ok
        
      // List<子类>并不是List<父类>的子类
//        t.tryInheritanceList(subList); // 参数类型List<SuperClass>，传入List<子类>，编译错误
//        t.tryInterfaceList(subList);  // 参数类型List<IParam>，传入List<实现类>，编译错误
        
        // 利用范型来解决问题
        t.tryGeneric(subList);  // 参数类型List<T extends IParam>，传入List<实现类>, ok
    }
}