Details
Major Description
When requesting Restful API {baseURL}/api/v1/applications/$appId/sql/$executionId which is introduced by this PR https://github.com/apache/spark/pull/28208, it can cause NullPointerException. The root cause is, when calling method doUpdate() of `LiveExecutionData`, `metricsValues` can be null. Then, when statement `printableMetrics(graph.allNodes, exec.metricValues)` is executed, it will throw NullPointerException.
