Sub.cs

using System;

abstract class TySub<A, B>
{
    public abstract B Cast(A a);
}

class TySub_Refl<A, B> : TySub<A, B>
  where A : B
{
    public override B Cast(A a)
    {
        return a;
    }
}

static class TySub_Helper
{
    public static TySub<A, B> Refl<A, B>()
        where A : B
    {
        return new TySub_Refl<A, B>();
    }
}

[SharpLab.Runtime.JitGeneric(typeof(string))]
class Hello<T>
{
    public void Store(TySub<T, ICloneable> ts, T value)
    {
        var c = ts.Cast(value);
        c.Clone();
    }
}

public static class C
{
    public static void M()
    {
        var hello = new Hello<String>();
        hello.Store(new TySub_Refl<string, ICloneable>(), "what");
    }
}

Sub.java

package example.playground.sub;

import lombok.Value;

import java.io.Serializable;

class Example<T> {
  void store(TySub<T, Serializable> ts, T value) {
    Serializable ser = ts.cast(value);
  }
}

// ---

abstract class TySub<A, B> {

  abstract B cast(A a);

  static <A extends B, B> TySub<A, B> refl() {
    return new Refl<>();
  }

  @Value
  static class Refl<A extends B, B> extends TySub<A, B> {
    @Override
    B cast(A a) {
      return a;
    }
  }
}

// ---

public class Program {
  public static void main(String[] args) {
    var ex = new Example<String>();
    ex.store(TySub.refl(), "hello");
  }
}