Source:
<code>public AzkabanWebServer(final Props props, final Server server, final ExecutorManager executorManager, final ProjectManager projectManager, final TriggerManager triggerManager, final MetricsManager metricsManager, final MetricRegistry metricRegistry, final SessionCache sessionCache, final UserManager userManager, final ScheduleManager scheduleManager, final VelocityEngine velocityEngine) { this.props = requireNonNull(props); this.server = requireNonNull(server); this.executorManager = requireNonNull(executorManager); this.projectManager = requireNonNull(projectManager); this.triggerManager = requireNonNull(triggerManager); this.metricsManager = requireNonNull(metricsManager); this.registry = requireNonNull(metricRegistry); this.sessionCache = requireNonNull(sessionCache); this.userManager = requireNonNull(userManager); this.scheduleManager = requireNonNull(scheduleManager); <START> this.velocityEngine = requireNonNull(velocityEngine); <END> loadBuiltinCheckersAndActions(); final String triggerPluginDir = props.getString("trigger.plugin.dir", "plugins/triggers"); loadPluginCheckersAndActions(triggerPluginDir); if (props.containsKey(DEFAULT_TIMEZONE_ID)) { final String timezone = props.getString(DEFAULT_TIMEZONE_ID); System.setProperty("user.timezone", timezone); TimeZone.setDefault(TimeZone.getTimeZone(timezone)); DateTimeZone.setDefault(DateTimeZone.forID(timezone)); logger.info("Setting timezone to " + timezone); } configureMBeanServer(); }</code><technical_language>check requireNonNull for injected classes guice? Is this practice for dependency injection</technical_language>

Target:
public AzkabanWebServer(final Props props, final Server server, final ExecutorManager executorManager, final ProjectManager projectManager, final TriggerManager triggerManager, final MetricsManager metricsManager, final MetricRegistry metricRegistry, final SessionCache sessionCache, final UserManager userManager, final ScheduleManager scheduleManager, final VelocityEngine velocityEngine) { this.props = requireNonNull(props, "props is null."); this.server = requireNonNull(server, "server is null."); this.executorManager = requireNonNull(executorManager, "executorManager is null."); this.projectManager = requireNonNull(projectManager, "projectManager is null."); this.triggerManager = requireNonNull(triggerManager, "triggerManager is null."); this.metricsManager = requireNonNull(metricsManager, "metricsManager is null."); this.registry = requireNonNull(metricRegistry, "metricRegistry is null."); this.sessionCache = requireNonNull(sessionCache, "sessionCache is null."); this.userManager = requireNonNull(userManager, "userManager is null."); this.scheduleManager = requireNonNull(scheduleManager, "scheduleManager is null."); this.velocityEngine = requireNonNull(velocityEngine, "velocityEngine is null."); loadBuiltinCheckersAndActions(); final String triggerPluginDir = props.getString("trigger.plugin.dir", "plugins/triggers"); loadPluginCheckersAndActions(triggerPluginDir); if (props.containsKey(DEFAULT_TIMEZONE_ID)) { final String timezone = props.getString(DEFAULT_TIMEZONE_ID); System.setProperty("user.timezone", timezone); TimeZone.setDefault(TimeZone.getTimeZone(timezone)); DateTimeZone.setDefault(DateTimeZone.forID(timezone)); logger.info("Setting timezone to " + timezone); } configureMBeanServer(); }