Tagged Questions

4
votes
4answers
76 views

generic type and assignment problems

I know that , every generic type variable replaced to upper bound that has been determined from the generic definition in the start of method "type-parameter section". this is from Deitel book ...
1
vote
2answers
36 views

Reference type dependency - declare Map.Entry to be dependent on generic types declared for TreeMap

let's imagine this scenario - I would like to use TreeMap in java. It's part of the Colletions framework and the only implementation of the SortedMap interface. public class MyDictionary extends ...
1
vote
1answer
44 views

maven refuses to compile generic class due to bounds, even after casting class

Here is a simplified version of the code I'm using to hold a generic list of children to a parent. Forgive me for having to rewrite this by hand instead of copy-past, There is no way to copy from ...
6
votes
1answer
71 views

Java generics, get Class<T> of generic parameter

I have an abstract class: public abstract class RootProcessor<T> { Class<T> clazz; } I need to fill ClassT clazz; with the children of RootProcessor - every child has its own T I ...
4
votes
7answers
99 views

Return reversed generic list-type in Java

I'm doing some exercises on generic programming; is there a way to take a class that implements List and return a reversed version of that same class? It seems this should be feasible as this, at ...
0
votes
2answers
28 views

Java Generic Parameter Bound In Instantiation

Having a major brain fart right now. I have this: public static final Map<WorkType, Class> handler; Then handler = new TreeMap<WorkType, Class>() {{ put(WorkType.SUBMIT, ...
0
votes
2answers
44 views

How to serialize Java generics with SimpleJson

I want to use a generic model to broadcast different data over websocket from server to client. Unfortunatley I always get an error while wanting to serialize the following class structure: Class to ...
2
votes
2answers
52 views

Generics: Cannot convert from Collections.emptyList() to List<String>

Why public List<String> getList(){ if (isMyListOKReady()) return myList; return Collections.emptyList(); } compiles well, but for public List<String> getList(){ ...
6
votes
8answers
179 views

Java generics, list of lists

This thing has me stumped. I have a class as follows: public class SpecialList implements List<MyType> { // overriden methods } Now I have the following method contract to respect in a ...
-1
votes
1answer
33 views

Reflect method get type of generics when the generics is String [closed]

This is mycode. I don't know when I want to get the type of generics used reflect method. I know the generics just run in Compilation time. when I used the Integer or other type, it'll Correctly. ...
0
votes
1answer
65 views

Yet another Java generics “incompatible types” compilation error

I was writing some code and came across a incompatible types compilation error. This is what I have: public interface Expression<T> { int getArity(); T evaluate(); } public abstract ...
-1
votes
0answers
31 views

Nested collections of arbitrary depth, generics

There are other, easier, ways of creating k-ary trees but I am trying to see if it is possible to create trees with generics where the root has direct access to all its descendants by way of nested ...
4
votes
2answers
142 views

Defining abstract math with java

I am trying to define some basic mathematical concepts in java, but keep getting stuck with generics errors. Consider the example below. In this example, I try to define the zero mapping (f(x) = 0 for ...
2
votes
1answer
61 views

Override generic methods through interfaces

I have some contents, generated by this interface: public interface Content { void addListener(ContentListener<?> listener); } Like GenericContent: public interface GenericContent ...
1
vote
2answers
39 views

Eliminate Intermediate Step in Cast

I am using import org.springframework.data.repository.support.Repositories to get an instance of a Spring Data Repository within a Quartz Job. The Repositories class has a ...

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