How to avoid standard inheritance of mixed type and inner classes?

Question

My class inherits from the parent class, which uses the common through grandparents. The same class also contains the inner class used for the builder. Since I am influencing a generic variable, I got a compilation warning.

Note: Child.java uses unchecked or unsafe operations.

Here is a simplified version of my project.

Other.java

public class Other
{}

Grandparent.java

public class GrandParent<T>
{
    protected T t;
}

Parent.java

public class Parent<T> extends GrandParent
{}

Child.java

public class Child extends Parent<Other>
{
    // Inner class
    public static class Inner
    {
        public void iDoUnsafeStuff(Other other) {
            Child child = new Child();
            child.t = other;
        }
    }
}

Below is a more detailed output of compiling using -Xlint:unchecked.

Child.java:8: warning: [unchecked] unchecked assignment to variable t as member of raw type GrandParent
        child.t = other;

What is the correct way in Java to use the generic type of grandparents?

In other words, how to make type Otherc iDoUnsafeStuff()according to the grandfather?

Please note that I want to understand what is wrong and not suppress the warning.

Answer 1

:

public class Parent<T> extends GrandParent

public class Parent<T> extends GrandParent<T>

Parent GrandParent .

T Parent protected T t; <<23 > .