#vulnerable code 
                                public WatcherContext getWatcherContext() throws MojoExecutionException {
        try {
            BuildService.BuildContext buildContext = getBuildContext();
            WatchService.WatchContext watchContext = getWatchContext(hub);


            return new WatcherContext.Builder()
                    .serviceHub(hub)
                    .buildContext(buildContext)
                    .watchContext(watchContext)
                    .config(extractWatcherConfig())
                    .logger(log)
                    .newPodLogger(createLogger("[[C]][NEW][[C]] "))
                    .oldPodLogger(createLogger("[[R]][OLD][[R]] "))
                    .mode(mode)
                    .project(project)

                    .useProjectClasspath(useProjectClasspath)
                    .clusterConfiguration(getClusterConfiguration())
                    .kubernetesClient(kubernetes)
                    .fabric8ServiceHub(getFabric8ServiceHub())
                    .build();
        } catch(IOException exception) {
            throw new MojoExecutionException(exception.getMessage());
        }
    } 
                            #location 21 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                public WatcherContext getWatcherContext() throws MojoExecutionException {
        try {
            BuildService.BuildContext buildContext = getBuildContext();
            WatchService.WatchContext watchContext = hub != null ? getWatchContext(hub) : null;

            return new WatcherContext.Builder()
                    .serviceHub(hub)
                    .buildContext(buildContext)
                    .watchContext(watchContext)
                    .config(extractWatcherConfig())
                    .logger(log)
                    .newPodLogger(createLogger("[[C]][NEW][[C]] "))
                    .oldPodLogger(createLogger("[[R]][OLD][[R]] "))
                    .mode(mode)
                    .project(project)
                    .useProjectClasspath(useProjectClasspath)
                    .clusterConfiguration(getClusterConfiguration())
                    .kubernetesClient(kubernetes)
                    .fabric8ServiceHub(getFabric8ServiceHub())
                    .build();
        } catch(IOException exception) {
            throw new MojoExecutionException(exception.getMessage());
        }
    }