1. Does the raw type linked list accept primitives or they automatically converted to wrapper class objects?
2. How come the equality check and equals method both are returning true?
3. How do I print all the values in the linked list?
Without the specifying the type the compiler will attempt to auto-box it to the appropriate object equivalent, Integer in your case. If you had been using an IDE it should have complained about there being no type specified.
Line 12 is suspect. You are comparing to references, which in this case, is returning true because of data pooling. You should not rely on this and use the equals() method instead. The following code returns false instead.