Alguem pode me ajudar por que está dando nullpointerexception? , já pesquise em outros topicos já tente achar o erro mas não encontro … 
segue o erro e as classes abaixo :
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
br.com.caelum.vraptor.InterceptionException: exception raised, check root cause for details: java.lang.NullPointerException
br.com.caelum.vraptor.interceptor.ExecuteMethodInterceptor.intercept(ExecuteMethodInterceptor.java:86)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ExceptionHandlerInterceptor.intercept(ExceptionHandlerInterceptor.java:69)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:61)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ParametersInstantiatorInterceptor.intercept(ParametersInstantiatorInterceptor.java:90)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:59)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InstantiateInterceptor.intercept(InstantiateInterceptor.java:42)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InterceptorListPriorToExecutionExtractor.intercept(InterceptorListPriorToExecutionExtractor.java:44)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.FlashInterceptor.intercept(FlashInterceptor.java:81)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ResourceLookupInterceptor.intercept(ResourceLookupInterceptor.java:67)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:56)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.DefaultRequestExecution.execute(DefaultRequestExecution.java:70)
br.com.caelum.vraptor.VRaptor$1.insideRequest(VRaptor.java:92)
br.com.caelum.vraptor.ioc.spring.SpringProvider.provideForRequest(SpringProvider.java:56)
br.com.caelum.vraptor.VRaptor.doFilter(VRaptor.java:89)
root cause
java.lang.NullPointerException
br.com.AromaNaWeb.imagens.Imagens.salva(Imagens.java:27)
br.com.AromaNaWeb.controller.ImagensController.upload(ImagensController.java:38)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
br.com.caelum.vraptor.interceptor.ExecuteMethodInterceptor.intercept(ExecuteMethodInterceptor.java:57)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ExceptionHandlerInterceptor.intercept(ExceptionHandlerInterceptor.java:69)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:61)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ParametersInstantiatorInterceptor.intercept(ParametersInstantiatorInterceptor.java:90)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:59)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InstantiateInterceptor.intercept(InstantiateInterceptor.java:42)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InterceptorListPriorToExecutionExtractor.intercept(InterceptorListPriorToExecutionExtractor.java:44)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.FlashInterceptor.intercept(FlashInterceptor.java:81)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ResourceLookupInterceptor.intercept(ResourceLookupInterceptor.java:67)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:56)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.DefaultRequestExecution.execute(DefaultRequestExecution.java:70)
br.com.caelum.vraptor.VRaptor$1.insideRequest(VRaptor.java:92)
br.com.caelum.vraptor.ioc.spring.SpringProvider.provideForRequest(SpringProvider.java:56)
br.com.caelum.vraptor.VRaptor.doFilter(VRaptor.java:89)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.29 logs.
classe imagenscontroller
package br.com.AromaNaWeb.controller;
import java.io.File;
import br.com.AromaNaWeb.imagens.Imagens;
import br.com.AromaNaWeb.modelo.Produto;
import br.com.caelum.vraptor.Path;
import br.com.caelum.vraptor.Post;
import br.com.caelum.vraptor.Resource;
import br.com.caelum.vraptor.Result;
import br.com.caelum.vraptor.Validator;
import br.com.caelum.vraptor.interceptor.multipart.UploadedFile;
import br.com.caelum.vraptor.validator.Validations;
import br.com.caelum.vraptor.*;
import static org.hamcrest.Matchers.*;
import static br.com.caelum.vraptor.view.Results.*;
@Resource
public class ImagensController {
private Validator validator;
private Imagens imagens;
private Result result;
private String pastaImagens;
public ImagensController(Validator validator, Imagens imagens, Result result) {
this.validator = validator;
this.imagens = imagens;
this.result = result;
}
@Post @Path("/produtos/{produto.id}/imagem")
public void upload(Produto produto, UploadedFile imagem,Validator validator) {
//validator.checking(new Validations() {{
// if (that(imagem, is(notNullValue()), "imagem", "imagem.nula")) {
//that(imagem.getContentType(), startsWith("image"), "imagem", "nao.eh.imagem");
//}
//}});
//validator.onErrorUse(logic()).redirectTo(ProdutosController.class).edita(produto.getId());
imagens.salva(imagem, produto);
result.redirectTo(ProdutosController.class).edita(produto.getId());
}
public File download(Produto produto) {
return imagens.mostra(produto);
}
public File mostra(Produto produto) {
return new File(pastaImagens, produto.getId() + ".imagem");
}
}
e classe imagens
package br.com.AromaNaWeb.imagens;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import javax.servlet.ServletContext;
import br.com.AromaNaWeb.modelo.Produto;
import br.com.caelum.vraptor.interceptor.multipart.UploadedFile;
import br.com.caelum.vraptor.ioc.Component;
import org.apache.commons.io.IOUtils;
@Component
public class Imagens {
private File pastaImagens;
public Imagens(ServletContext context) {
String caminhoImagens = context.getRealPath("/WebContent/imagens");
pastaImagens = new File(caminhoImagens);
pastaImagens.mkdir();
}
public void salva(UploadedFile imagem, Produto produto) {
File destino = new File(pastaImagens, produto.getId() + ".imagem");
try {
IOUtils.copyLarge(imagem.getFile(), new FileOutputStream(destino));
} catch (IOException e) {
throw new RuntimeException("Erro ao copiar imagem", e);
}
}
public File mostra(Produto produto) {
return new File(pastaImagens, produto.getId() + ".imagem");
}
}
se alguem puder me ajudar .
