#fixed code
                                public final void addThumbnail(final JcrPackage jcrPackage, Resource thumbnailResource) {
        ResourceResolver resourceResolver = null;

        if (jcrPackage == null) {
            log.error("JCR Package is null; no package thumbnail needed for null packages!");
            return;
        }

        boolean useDefault = thumbnailResource == null || !thumbnailResource.isResourceType(JcrConstants.NT_FILE);

        try {
            if (useDefault) {
                log.debug("Using default ACS AEM Commons packager package icon.");
                resourceResolver = resourceResolverFactory.getAdministrativeResourceResolver(null);
                thumbnailResource = resourceResolver.getResource(DEFAULT_PACKAGE_THUMBNAIL_RESOURCE_PATH);
            }

            if (thumbnailResource == null || !thumbnailResource.isResourceType(JcrConstants.NT_FILE)) {
                log.warn("Cannot find a specific OR a default package icon; no package icon will be used.");
            } else {
                final Node srcNode = thumbnailResource.adaptTo(Node.class);
                final Node dstParentNode = jcrPackage.getDefinition().getNode();

                JcrUtil.copy(srcNode, dstParentNode, NN_THUMBNAIL);
                dstParentNode.getSession().save();
            }
        } catch (RepositoryException e) {
            log.error("Could not add package thumbnail: {}", e.getMessage());
        } catch (LoginException e) {
            log.error("Could not add a default package thumbnail: {}", e.getMessage());
        } finally {
            if (resourceResolver != null) {
                resourceResolver.close();
            }
        }
    }
#vulnerable code 
                                public final void addThumbnail(final JcrPackage jcrPackage, Resource thumbnailResource) {
        ResourceResolver resourceResolver = null;

        if (jcrPackage == null) {
            log.error("JCR Package is null; no package thumbnail needed for null packages!");
            return;
        }

        boolean useDefault = thumbnailResource == null || !thumbnailResource.isResourceType(JcrConstants.NT_FILE);

        try {
            if (useDefault) {
                log.debug("Using default ACS AEM Commons packager package icon.");
                resourceResolver = resourceResolverFactory.getAdministrativeResourceResolver(null);
                thumbnailResource = resourceResolver.getResource(DEFAULT_PACKAGE_THUMBNAIL_RESOURCE_PATH);

                if (thumbnailResource == null || !thumbnailResource.isResourceType(JcrConstants.NT_FILE)) {
                    log.warn("Cannot find a specific OR a default package icon; no package icon will be used.");
                }
            }

            final Node srcNode = thumbnailResource.adaptTo(Node.class);
            final Node dstParentNode = jcrPackage.getDefinition().getNode();

            JcrUtil.copy(srcNode, dstParentNode, NN_THUMBNAIL);
            dstParentNode.getSession().save();
        } catch (RepositoryException e) {
            log.error("Could not add package thumbnail: {}", e.getMessage());
        } catch (LoginException e) {
            log.error("Could not add a default package thumbnail: {}", e.getMessage());
        } finally {
            if (resourceResolver != null) {
                resourceResolver.close();
            }
        }
    } 
                            #location 22 
                            #vulnerability type NULL_DEREFERENCE