updates per issue #928

dependency-check-core/src/main/java/org/owasp/dependencycheck/dependency/Dependency.java

@@ -752,6 +752,7 @@ public class Dependency extends EvidenceCollection implements Serializable {
                 .append(actualFilePath)
                 .append(filePath)
                 .append(fileName)
+                .append(packagePath)
                 .append(md5sum)
                 .append(sha1sum)
                 .append(identifiers)

dependency-check-core/src/main/java/org/owasp/dependencycheck/dependency/Evidence.java

@@ -209,7 +209,7 @@ public class Evidence implements Serializable, Comparable<Evidence> {
     @Override
     public int compareTo(Evidence o) {
         if (o == null) {
-            return 1;
+            throw new NullPointerException("Unable to compare null evidence");
         }
         if (StringUtils.equalsIgnoreCase(source, o.source)) {
             if (StringUtils.equalsIgnoreCase(name, o.name)) {

dependency-check-core/src/main/java/org/owasp/dependencycheck/dependency/Identifier.java

@@ -262,7 +262,7 @@ public class Identifier implements Serializable, Comparable<Identifier> {
     @Override
     public int compareTo(Identifier o) {
         if (o == null) {
-            return -1;
+            throw new NullPointerException("Unable to compare a null identifier");
         }
         return new CompareToBuilder()
                 .append(this.type, o.type)