#vulnerable code 
                                private boolean addProvisionedSlave(@Nonnull PodTemplate template, @CheckForNull Label label) throws Exception {
        if (containerCap == 0) {
            return true;
        }

        KubernetesClient client = connect();
        String templateNamespace = template.getNamespace();
        // If template's namespace is not defined, take the
        // Kubernetes Namespace.
        if (Strings.isNullOrEmpty(templateNamespace)) {
            templateNamespace = client.getNamespace();
        }

        PodList slaveList = client.pods().inNamespace(templateNamespace).withLabels(getLabels()).list();
        List<Pod> allActiveSlavePods = null;
        // JENKINS-53370 check for nulls
        if (slaveList != null && slaveList.getItems() != null) {
            allActiveSlavePods = slaveList.getItems().stream() //
                    .filter(x -> x.getStatus().getPhase().toLowerCase().matches("(running|pending)"))
                    .collect(Collectors.toList());
        }

        Map<String, String> labelsMap = new HashMap<>(this.getLabels());
        labelsMap.putAll(template.getLabelsMap());
        PodList templateSlaveList = client.pods().inNamespace(templateNamespace).withLabels(labelsMap).list();
        List<Pod> activeTemplateSlavePods = templateSlaveList.getItems().stream()
                .filter(x -> x.getStatus().getPhase().toLowerCase().matches("(running|pending)"))
                .collect(Collectors.toList());

        if (allActiveSlavePods != null && containerCap <= allActiveSlavePods.size()) {
            LOGGER.log(Level.INFO,
                    "Total container cap of {0} reached, not provisioning: {1} running or pending in namespace {2} with Kubernetes labels {3}",
                    new Object[] { containerCap, allActiveSlavePods.size(), templateNamespace, getLabels() });
            return false;
        }

        if (activeTemplateSlavePods != null && allActiveSlavePods != null && template.getInstanceCap() <= activeTemplateSlavePods.size()) {
            LOGGER.log(Level.INFO,
                    "Template instance cap of {0} reached for template {1}, not provisioning: {2} running or pending in namespace {3} with label \"{4}\" and Kubernetes labels {5}",
                    new Object[] { template.getInstanceCap(), template.getName(), allActiveSlavePods.size(),
                            templateNamespace, label == null ? "" : label.toString(), labelsMap });
            return false;
        }
        return true;
    } 
                            #location 26 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                private boolean addProvisionedSlave(@Nonnull PodTemplate template, @CheckForNull Label label) throws Exception {
        if (containerCap == 0) {
            return true;
        }

        KubernetesClient client = connect();
        String templateNamespace = template.getNamespace();
        // If template's namespace is not defined, take the
        // Kubernetes Namespace.
        if (Strings.isNullOrEmpty(templateNamespace)) {
            templateNamespace = client.getNamespace();
        }

        PodList slaveList = client.pods().inNamespace(templateNamespace).withLabels(getLabels()).list();
        List<Pod> allActiveSlavePods = null;
        // JENKINS-53370 check for nulls
        if (slaveList != null && slaveList.getItems() != null) {
            allActiveSlavePods = slaveList.getItems().stream() //
                    .filter(x -> x.getStatus().getPhase().toLowerCase().matches("(running|pending)"))
                    .collect(Collectors.toList());
        }

        Map<String, String> labelsMap = new HashMap<>(this.getLabels());
        labelsMap.putAll(template.getLabelsMap());
        PodList templateSlaveList = client.pods().inNamespace(templateNamespace).withLabels(labelsMap).list();
        // JENKINS-53370 check for nulls
        List<Pod> activeTemplateSlavePods = null;
        if (templateSlaveList != null && templateSlaveList.getItems() != null) {
            activeTemplateSlavePods = templateSlaveList.getItems().stream()
                    .filter(x -> x.getStatus().getPhase().toLowerCase().matches("(running|pending)"))
                    .collect(Collectors.toList());
        }

        if (allActiveSlavePods != null && containerCap <= allActiveSlavePods.size()) {
            LOGGER.log(Level.INFO,
                    "Total container cap of {0} reached, not provisioning: {1} running or pending in namespace {2} with Kubernetes labels {3}",
                    new Object[] { containerCap, allActiveSlavePods.size(), templateNamespace, getLabels() });
            return false;
        }

        if (activeTemplateSlavePods != null && allActiveSlavePods != null && template.getInstanceCap() <= activeTemplateSlavePods.size()) {
            LOGGER.log(Level.INFO,
                    "Template instance cap of {0} reached for template {1}, not provisioning: {2} running or pending in namespace {3} with label \"{4}\" and Kubernetes labels {5}",
                    new Object[] { template.getInstanceCap(), template.getName(), allActiveSlavePods.size(),
                            templateNamespace, label == null ? "" : label.toString(), labelsMap });
            return false;
        }
        return true;
    }