Java APIs

Consider the following serialization/deserialization test class:

import java.io.*;
import java.util.*;

public class TestSerialzationAndGenerics {
	
	public static void main(String[] args) throws Exception {
		List listUntyped = new ArrayList();
		Set<Object> setTyped = new HashSet<Object>();
		
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		ObjectOutputStream oos = new ObjectOutputStream( baos );
		oos.writeObject( listUntyped );
		oos.writeObject( setTyped );
		
		ObjectInputStream ois = new ObjectInputStream( new ByteArrayInputStream( baos.toByteArray() ) );
		List listUntypedDeser = (List) ois.readObject();
		Set<Object> setTypedDeser = (Set<Object>) ois.readObject();
		
		System.out.println("listUntyped.equals(listUntypedDeser): " + listUntyped.equals(listUntypedDeser));
		System.out.println("setTyped.equals(setTypedDeser): " + setTyped.equals(setTypedDeser));
	}
	
}

Critical: compile it with

	-Xlint:all

Then run it. It should work just fine, outputting:

	listUntyped.equals(listUntypedDeser): true
	setTyped.equals(setTypedDeser): true

as expected.

My question actually concerns the compilation step: why does the line

		List listUntypedDeser = (List) ois.readObject();

compile just fine, but the line

		Set<Object> setTypedDeser = (Set<Object>) ois.readObject();

cause javac to emit this warning:

		TestSerialzationAndGenerics.java:17: warning: [unchecked] unchecked cast
		found   : java.lang.Object
		required: java.util.Set<java.lang.Object>

? Both lines are just casts after all, but one is an untyped Collection cast while the other one is a cast to a generified Collection. For some reason, javac seems to have a problem with generified casts.

Am I doing something wrong?

Is there any way around this?

A google search only turned up 3 relevant postings, with only 1 in english:
http://forum.java.sun.com/thread.jspa?messageID=3655969
This forum posting touches on this issue, but they never addressed my question above which is why the generified cast is a problem when the untyped cast is not.

Eargerly awaiting your thoughts...