Java Compiler error with multiple generics type

Question

I have a interface like this:

public interface GenericWSEndpoint<T1,T2> {

    public void call(String url,String operationName, T1 requestObject, T2 responseObject,long timeout) throws Exception;

}

When I try to define an object with this, it gives

org.apache.maven.BuildFailureException: Compilation failure : incompatible types

Object definition:

private static GenericWSEndpoint<BulkCheckBlockageRequest,BulkCheckBlockageResponse> endpoint=GenericWsEndpointFactory.createSpecificEndpoint(WSTypes.CXF);

And factory code:

public class GenericWsEndpointFactory{

    public static <T1,T2> GenericWSEndpoint createSpecificEndpoint(WSTypes type){
        switch (type) {
        case CXF:

            return new CXFWsEndPoint<T1,T2>();
        }

        return null;
    }

}

and the CXFWsEndPoint(no constructors defined specificly):

public class CXFWsEndPoint<T1,T2> implements GenericWSEndpoint<T1, T2>{
.
.
}

I have checked the answers about this problem but they are related with definitions like recursive generics

Any ideas?

EDIT: Exception:

[INFO] Compilation failure ResponseManager\src\main\java\com\x\resman\util\WebServiceUtil.java:[57,142] incompatible types; no instance(s) of type variable(s) T1,T2 exist so that com.x.rbm.ws.service.GenericWSEndpoint conforms to com.x.rbm.ws.service.GenericWSEndpoint found : com.x.rbm.ws.service.GenericWSEndpoint required:

com.x.rbm.ws.service.GenericWSEndpointequest,com.x.resman.model.checkblockage.BulkCheckBlockageResponse>

Check your right-hand side type, of what type is GenericWsEndpointFactory.createSpecificEndpoint(WSTypes.CXF); ? — Christophe Roussy
– Christophe Roussy, Commented Jul 8, 2013 at 8:31

Christophe Roussy · Accepted Answer · 2013-07-08 08:52:44Z

2

Try with the following code:

  public static <T1, T2> GenericWSEndpoint<T1, T2> createSpecificEndpoint() {

instead of

  public static <T1, T2> GenericWSEndpoint createSpecificEndpoint() {

answered Jul 8, 2013 at 8:52

Christophe Roussy

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4 Comments

Christophe Roussy Over a year ago

Which IDE are you using (if any) ?

Christophe Roussy Over a year ago

You should get a warning on that line for this kind of problem (maybe it is an optional one).

Neron Over a year ago

yes but it should not be a warning if it is gonna give a compiler error.

Christophe Roussy Over a year ago

Maybe Eclipse is badly configured and should show it as an error (can be configured). Let me know if you figure this out.

APinto · Accepted Answer · 2013-07-08 08:46:38Z

0

Are you specifying the Java source version in your Maven POM file? Currently, by default Maven uses 1.5. You probably need something more recent. What version are you using in our IDE?

The relevant Maven configuration is:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <source>1.7</source>
        <target>1.7</target>
    </configuration>
</plugin>

Hope this helps.

answered Jul 8, 2013 at 8:46

APinto

767 bronze badges

1 Comment

Neron Over a year ago

I have 1.6 version in maven and it is compatible with generics. It is not a maven problem also

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