...
According to the Java Language Specification, §4.8, "Raw Types," [JLS 2005]:
The use of raw types is allowed only as a concession to compatibility of legacy code. The use of raw types in code written after the introduction of genericity into the Java programming language is strongly discouraged. It is possible that future versions of the Java programming language will disallow the use of raw types.
...
The compiler prevents insertion of an Object to the parameterized list because addToList() cannot be called with an argument whose type produces a mismatch. This code has consequently been changed to add a String to the list instead of an int.
...