3- Assume that you want to design a linked list that has nodes that contain the following fields: an integer key, a double d and a link to the node following the next node as well as a link to the previous node. Write the class definition for the node (member variables only, no need for methods), and the class definition for the List (member variables only, no methods) 3.1 Assume that you have the following List, write the portion of Java code to insert temp node (8) between nodes 7 and 9 Ref 10 31.4 2.3 22.5 Temp 12.8 3.2 Write the code that allows you to insert a node N in the front of the list assuming that first references the first node in the list. .3 Write the java code that allows you to insert node N in the Tail of the list, assuming that last references the last node in list