FULL PRODUCT VERSION :
java version "1.5.0_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
When iterating over generic iterable elements with the enhanced for-each loop, and you do not use typeinformation in the loop, you get a ClassCastException runtime. One would expect this not to happen, since we do not use the generic type information in the for-each loop, but the compiled code still does a cast.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the attached java file, and run it.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected result was to see a regular run of the program with no errors.
ACTUAL -
The actual result is a classcastexception

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.lang.ClassCastException: ForEachBug$B
        at ForEachBug.reproduceBug(ForEachBug.java:19)
        at ForEachBug.main(ForEachBug.java:10)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.ArrayList;
import java.util.List;

public class ForEachBug {
	public class A {}

	public class B {}

	public static void main(String[] args) {
		new ForEachBug().reproduceBug();

	}

	private void reproduceBug() {
		List list = new ArrayList();
		list.add(new B());
		List<A> aList = new ArrayList<A>();
		aList.addAll(list);
		for (Object a : aList) {
			System.out.println(a);
		}
	}

}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
make sure you do not use @supressWarnings("unchecked"), and remove all type safety warnings in your code.