avoid polluting logs with long stacktraces when a request comes in for a report from an unbuilt job (a fairly common case in archive-it)

engine/src/main/java/org/archive/crawler/restlet/JobRelatedResource.java

@@ -22,7 +22,6 @@ package org.archive.crawler.restlet;
 import java.beans.IntrospectionException;
 import java.beans.PropertyDescriptor;
 import java.io.File;
-import java.io.PrintWriter;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
@@ -44,7 +43,6 @@ import org.restlet.data.Response;
 import org.restlet.resource.ResourceException;
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeanWrapperImpl;
-import org.springframework.beans.InvalidPropertyException;
 
 /**
  * Shared superclass for resources that represent functional aspects

engine/src/main/java/org/archive/crawler/restlet/ReportGenResource.java

@@ -47,6 +47,9 @@ public class ReportGenResource extends JobRelatedResource {
 
     public Representation represent(Variant variant) throws ResourceException {
         // generate report
+        if (cj == null || cj.getCrawlController() == null) {
+            throw new ResourceException(500);
+        }
         File f = cj.getCrawlController().getStatisticsTracker().writeReportFile(reportClass); 
         if (f==null) {
             throw new ResourceException(500);