Custom generic Classes

1 when instantiating an object of a generic class, indicate the type of the generic class. When specified, all locations in the corresponding class that use generics become the type of the generic that is specified in the instantiation

2 If we customize a generic class, but are not used when instantiating it, the default type is the object class.

 PackageLianxi3;Importjava.util.ArrayList;Importjava.util.List;Importorg.junit.Test;//Custom Generic Classes Public classOrder<t> {    Private intorderId; PrivateString Ordername; PrivateT T; List<T> list =NewArraylist<t>(); //methods for declaring generic classes     Public<E>e Gete (e e) {returne; }    //implementing array-to-collection replication     Public<e>list Fromarrtolist (e[]e,list<e>List1) {         for(E e1:e) {list1.add (E1); }        returnList1; }     Public voidAdd () {List.add (t); }     Public intGetorderid () {returnorderId; }     Public voidSetorderid (intorderId) {         This. OrderId =orderId; }     PublicString Getordername () {returnOrdername; }     Public voidsetordername (String ordername) { This. Ordername =Ordername; }     PublicT Gett () {returnT; }     Public voidsett (t t) { This. T =T; } @Override PublicString toString () {return"Order [orderid=" + OrderId + ", ordername=" +Ordername+ ", t=" + t + "]"; }}//1.class suborder<t> extends order<t>{classSuborderextendsOrder<boolean>{    }

@Test//Customizing the use of generic classes     Public voidtest3 () {Order<String> O1 =NewOrder<string>(); O1.setorderid (32); O1.setordername ("FAs"); O1.sett ("TT");        System.out.println (O1);        O1.add (); //list<string> list1 = o1.list;//The list in O1 holds data of type stringSystem.out.println (o1.list);//or System.out.println (List1); //methods for declaring generic classesInteger I1 = O1.gete (789); System.out.println ("I1=" +i1); //1.suborder<boolean> so = new suborder<boolean> ();Suborder so =Newsuborder (); So.setorderid (34); So.sett (true);        So.add (); So.sett (true);        So.add (); So.sett (false);        So.add ();    System.out.println (so.list); //implementing array-to-collection replicationInteger[] in =Newinteger[]{3,5,6}; List<Integer> List1 =NewArraylist<integer>();        O1.fromarrtolist (in, List1);            System.out.println (List1); }

Results:

Order [Orderid=32, Ordername=fas, T=tt]
[TT]
i1=789
[True, True, false]
[3, 5, 6]

Custom generic Classes