#vulnerable code 
                                @Override
    public void buildVariablesFor(AbstractBuild build, Map<String, String> variables) {
        final Executor executor = build.getExecutor();
        if (executor != null && executor.getOwner() instanceof DockerComputer) {
            final DockerComputer dockerComputer = (DockerComputer) executor.getOwner();
            variables.put("DOCKER_CONTAINER_ID", dockerComputer.getContainerId());
            variables.put("JENKINS_CLOUD_ID", dockerComputer.getCloudId());

            final DockerCloud cloud = dockerComputer.getCloud();
            if (cloud.isExposeDockerHost()) {
                //replace http:// and https:// from docker-java to tcp://
                String dockerHost = cloud.getDockerHost().getUri();
                if (dockerHost.startsWith("unix:")) {
                    dockerHost = "tcp:" + dockerHost.substring(5);
                }
                variables.put("DOCKER_HOST", dockerHost);
            }
        }
    } 
                            #location 10 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public void buildVariablesFor(AbstractBuild build, Map<String, String> variables) {
        final Executor executor = build.getExecutor();
        if (executor != null && executor.getOwner() instanceof DockerComputer) {
            final DockerComputer dockerComputer = (DockerComputer) executor.getOwner();
            variables.put("DOCKER_CONTAINER_ID", dockerComputer.getContainerId());
            variables.put("JENKINS_CLOUD_ID", dockerComputer.getCloudId());

            final DockerCloud cloud = dockerComputer.getCloud();
            if (cloud != null && cloud.isExposeDockerHost()) {
                //replace http:// and https:// from docker-java to tcp://
                String dockerHost = cloud.getDockerHost().getUri();
                if (dockerHost.startsWith("unix:")) {
                    dockerHost = "tcp:" + dockerHost.substring(5);
                }
                variables.put("DOCKER_HOST", dockerHost);
            }
        }
    }