How can I add to List<? extends Number> data structures?

Posted by kunjaan on Stack Overflow See other posts from Stack Overflow or by kunjaan
Published on 2010-05-05T21:38:00Z Indexed on 2010/05/07 19:38 UTC
Read the original article Hit count: 114

Filed under:

java

|

generics

I have a List which is declared like this :

 List<? extends Number> foo3 = new ArrayList<Integer>();

I tried to add 3 to foo3. However I get an error message like this:

The method add(capture#1-of ? extends Number) in the type List<capture#1-of ?
extends Number> is not applicable for the arguments (ExtendsNumber)

© Stack Overflow or respective owner

Related posts about java

Tomcat 6: Access Control Exception?

as seen on Server Fault - Search for 'Server Fault'
I'm trying to setup a tomcat6 server, and I'm trying to match another setup someone else established. However, my deployment (default Ubuntu install) uses a policy.d/ directory structure, and the established server just uses a catalina.policy file. I've tried setting every entry in policy.d to match… >>> More
Problem in creation MDB Queue connection at Jboss StartUp

as seen on Stack Overflow - Search for 'Stack Overflow'
I am not able to create a Queue connection in JBOSS4.2.3GA Version & Java1.5, as I am using MDB as per the below details. I am putting this MDB in a jar file(named utsJar.jar) and copied it in deploy folder of JBOSS, In the test env. this MDB works well but in another env. [ env settings and… >>> More
failing to establish connection between Postgres db and gwt

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am using Postgres and gwt 2.0 for one of my applications. I am facing problem connecting to the database. When I try to connect it gives "ClassNotFoundException". Here is what I get when I try to connect to database: java.lang.ClassNotFoundException: org.postgresql.Driver at java.net… >>> More
failing to establish connection between postgre db and gwt

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, For i am using postgre and gwt 2.0 for one of my applications. I am facing problem connecting to the database. When i try to connect it gives "ClassNotFoundException". Here is what i get when i try to connect to database: java.lang.ClassNotFoundException: org.postgresql.Driver at java.net… >>> More
Migration and deployement problems JBoss 4.2.2.GA to JBoss 6.0.0.M2

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I'm trying to migrate an application running on JBoss 4.2.2.GA to JBoss 6.0.0.M2 I give you some log to explain my problem : boot.log : 2010-03-16 09:59:29,406 ERROR [org.jboss.system.server.profileservice.ProfileServiceBootstrap] (Thread-2) Failed to load profile: Summary of incomplete deployments… >>> More

Related posts about generics

Java generics: What is the compiler's issue here?

as seen on Stack Overflow - Search for 'Stack Overflow'
I have the following methods: public <T> T fromJson( Reader jsonData, Class<T> clazz ) { return fromJson( jsonData, (Type)clazz ); } public <T> T fromJson( Reader jsonData, Type clazz ) { ... } The compiler is saying about the first method: type parameters of <T>T… >>> More
Why does NUnit ignore datapoints when using generics in a theory

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to make use of the TheoryAttribute, introduced in NUnit 2.5. Everything works fine as long as the arguments are of a defined type: [Datapoint] public double[,] Array2X2 = new double[,] { { 1, 0 }, { 0, 1 } }; [Theory] public void TestForArbitraryArray(double[,] array) { // ... } It… >>> More
Instantiating generics type in java

as seen on Stack Overflow - Search for 'Stack Overflow'
I would like to create an object of Generics Type in java. Please suggest how can I achieve the same. suppose I have the class declaration as: public class Abc<T> { public static void main(String[] args) { // I want to create an instance of T } } >>> More
.NET converting simple arrays to List Generics

as seen on Stack Overflow - Search for 'Stack Overflow'
This question might seem trivial and also stupid at the first glance, but it is much more than this. I have an array of any type T (T[]) and I want to convert it into a List generic (List<T>). Is there any other way apart from creating a Generic list, traversing the whole array and adding the… >>> More
Instantiating a list of parameterized types, making beter use of Generics and Linq

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm hashing a file with one or more hash algorithms. When I tried to parametrize which hash types I want, it got a lot messier than I was hoping. I think I'm missing a chance to make better use of generics or LINQ. I also don't like that I have to use a Type[] as the parameter instead of limiting… >>> More