Reified generics in Java

Test.java

import java.util.*;

@SuppressWarnings("ALL")
class Test {
  static class ReifiedList<T> extends AbstractList<T> {
    private final List<T> delegate = new ArrayList<>();
    private final Class<?> type;

    @SafeVarargs
    ReifiedList(@Deprecated T... unused) {
      if (unused == null || unused.length != 0) {
        throw new IllegalArgumentException();
      }
      type = unused.getClass().getComponentType();
    }

    public T typeCheck(T element) {
      if (!type.isInstance(element)) {
        throw new IllegalArgumentException();
      }
      return element;
    }

    public boolean add(T element) { return delegate.add(typeCheck(element)); }
    public T set(int index, T element) { return delegate.set(index, typeCheck(element)); }

    public T get(int index) { return delegate.get(index); }
    public int size() { return delegate.size(); }
    public boolean equals(Object o) { return o == this || delegate.equals(o); }
    public int hashCode() { return delegate.hashCode(); }
    public String toString() { return delegate.toString(); }
  }
  
  public static void main(String[] args) {
    List<String> list = new ReifiedList<>();
    list.add("foo");
    ((List) list).add(1); // Exception in thread "main" java.lang.IllegalArgumentException
    System.out.println(list);
  }
}

Nice trick!