java - Dozer unable to map Collection<Interface> member -

i have object contains collection:

public class wrapper {     private collection<base> bases = new linkedlist<base>();     public collection<base> getbases() {return bases;}     public void setbases(final collection<base> bases) {this.bases = bases;} } 

the implementations of interface quite simple:

public class baseone implements base { }  public class basetwo implements base { } 

when run simple test:

@test public void testcopyother() {     final wrapper wrapper =  new wrapper();     wrapper.getbases().add(new baseone());      final wrapper copy = dozer.map(wrapper, wrapper.class); } 

i exception:

org.dozer.mappingexception: java.lang.nosuchmethodexception: com.usamp.biddingtool.model.service.impl.base.<init>()     @ org.dozer.util.mappingutils.throwmappingexception(mappingutils.java:82)     @ org.dozer.factory.constructionstrategies$byconstructor.newinstance(constructionstrategies.java:261)     @ org.dozer.factory.constructionstrategies$byconstructor.create(constructionstrategies.java:245)     @ org.dozer.factory.destbeancreator.create(destbeancreator.java:65)     @ org.dozer.mappingprocessor.mapcustomobject(mappingprocessor.java:489)     @ org.dozer.mappingprocessor.maporrecurseobject(mappingprocessor.java:446)     @ org.dozer.mappingprocessor.addorupdatetolist(mappingprocessor.java:776)     @ org.dozer.mappingprocessor.addorupdatetolist(mappingprocessor.java:850)     @ org.dozer.mappingprocessor.maplisttolist(mappingprocessor.java:686)     @ org.dozer.mappingprocessor.mapcollection(mappingprocessor.java:541)     @ org.dozer.mappingprocessor.maporrecurseobject(mappingprocessor.java:434)     @ org.dozer.mappingprocessor.mapfromfieldmap(mappingprocessor.java:342)     @ org.dozer.mappingprocessor.mapfield(mappingprocessor.java:288)     @ org.dozer.mappingprocessor.map(mappingprocessor.java:248)     @ org.dozer.mappingprocessor.map(mappingprocessor.java:197)     @ org.dozer.mappingprocessor.map(mappingprocessor.java:187)     @ org.dozer.mappingprocessor.map(mappingprocessor.java:124)     @ org.dozer.mappingprocessor.map(mappingprocessor.java:119)     @ org.dozer.dozerbeanmapper.map(dozerbeanmapper.java:120)     @ com.usamp.biddingtool.model.service.impl.dozertest.testcopyother(dozertest.java:52)     @ sun.reflect.nativemethodaccessorimpl.invoke0(native method)     @ sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:57)     @ sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:43)     @ org.junit.runners.model.frameworkmethod$1.runreflectivecall(frameworkmethod.java:47)     @ org.junit.internal.runners.model.reflectivecallable.run(reflectivecallable.java:12)     @ org.junit.runners.model.frameworkmethod.invokeexplosively(frameworkmethod.java:44)     @ org.junit.internal.runners.statements.invokemethod.evaluate(invokemethod.java:17)     @ org.springframework.test.context.junit4.statements.runbeforetestmethodcallbacks.evaluate(runbeforetestmethodcallbacks.java:74)     @ org.springframework.test.context.junit4.statements.runaftertestmethodcallbacks.evaluate(runaftertestmethodcallbacks.java:83)     @ org.springframework.test.context.junit4.statements.springrepeat.evaluate(springrepeat.java:72)     @ org.springframework.test.context.junit4.springjunit4classrunner.runchild(springjunit4classrunner.java:231)     @ org.springframework.test.context.junit4.springjunit4classrunner.runchild(springjunit4classrunner.java:88)     @ org.junit.runners.parentrunner$3.run(parentrunner.java:238)     @ org.junit.runners.parentrunner$1.schedule(parentrunner.java:63)     @ org.junit.runners.parentrunner.runchildren(parentrunner.java:236)     @ org.junit.runners.parentrunner.access$000(parentrunner.java:53)     @ org.junit.runners.parentrunner$2.evaluate(parentrunner.java:229)     @ org.springframework.test.context.junit4.statements.runbeforetestclasscallbacks.evaluate(runbeforetestclasscallbacks.java:61)     @ org.springframework.test.context.junit4.statements.runaftertestclasscallbacks.evaluate(runaftertestclasscallbacks.java:71)     @ org.junit.runners.parentrunner.run(parentrunner.java:309)     @ org.springframework.test.context.junit4.springjunit4classrunner.run(springjunit4classrunner.java:174)     @ org.junit.runner.junitcore.run(junitcore.java:160)     @ com.intellij.junit4.junit4ideatestrunner.startrunnerwithargs(junit4ideatestrunner.java:77)     @ com.intellij.rt.execution.junit.junitstarter.preparestreamsandstart(junitstarter.java:195)     @ com.intellij.rt.execution.junit.junitstarter.main(junitstarter.java:63)     @ sun.reflect.nativemethodaccessorimpl.invoke0(native method)     @ sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:57)     @ com.intellij.rt.execution.application.appmain.main(appmain.java:120) 

so, seems dozer trying create instance of actual type being used in collection while type interface. since interfaces cannot instantiated error produced.

i have seen others ask question, not specific answer. there solutions issue?

thanks. -ap_

you have give hint dozer implementation of base. otherwise try instantiate interface , not possible. <mapping> <class-a>wrapper</class-a> <class-b>wrapper</class-b> <field> <a>bases</a> <b>bases</b> <a-hint>baseone,basetwo</a-hint> <b-hint>baseone,basetwo</b-hint> </field> </mapping>

http://dozer.sourceforge.net/documentation/baseattributes.html

alternative (update): <mapping> <class-a>baseone</class-a> <class-b>baseone</class-b> </mapping> <mapping> <class-a>basetwo</class-a> <class-b>basetwo</class-b> </mapping>