Java generics in constructor

package com.mycompany.genericissue;

import org.junit.Test;
import static org.junit.Assert.*;

/**
 *
 * @author lauri
 */
public class ContainerTest {

    @Test
    public void testIsFineOk() {
        // passing explicit byte
        Container<Byte> container = new Container((byte) 1);

        // all right
        byte value = valueOf(container);
        assertEquals(1, value);
    }

    @Test
    public void testWhichWillFail() {
        // note how value to contsructor passed. Type conversion expected to be here.
        Container<Byte> container = new Container(1);

        // but actually integer was allowed and so we're going to fail on next line
        byte value = valueOf(container);
        assertEquals(1, value);
    }

    private byte valueOf(Container<Byte> container) {
        return container == null ? -1 : container.getItem();
    }

    /**
     * Imaginary class with generic value to hold
     *
     * @param <T>
     */
    private static class Container<T> {

        private T item;

        public Container(T item) {
            this.item = item;
        }

        public T getItem() {
            return item;
        }
    }
}