java "generic generic type" -

in application, have board. board consists of cell. each cell has int value. there few types of boards extend board. each type of board represent cells differently. example, 1 use list , anothr use tree.

so tried:

public abstract class board<t> {     t<cell> cells;  //error - type t not generic; cannot parameterized arguments <cell>      protected abstract void setvalues(t<integer> values); } 

unfortunately, can't make t generic type. how implement that?

i found approach complicated. peter.petrov close do.

if list , tree (treeset) need, both implements interface collection why not use ?? need work beside of add, removing, iterating ?

collection (javadoc)

so class (i added little bit java8 features)

public abstract class board {     collection<cell> cells;        // don't need abstract     protected void setvalues(collection<integer> values) {         stream<cell> transformed = values.stream().map(cell::new);         cells.addall(transformed.collect(collectors.tolist()));     } }  class cell {     private integer value;      cell(integer value) {         this.value = value;     } } 

if need (for reason extra, extend class , implement/override methods special behaviour). helped, don't see use case example.