public static void initialize(MetadataDAO metadataDAO) {
        ValidationContext.metadataDAO = metadataDAO;
    }
This context is defined to get access to {@link MetadataDAO} inside {@link
WorkflowTaskTypeConstraint} constraint validator to validate {@link
com.netflix.conductor.common.metadata.workflow.WorkflowTask}.
core/src/main/java/com/netflix/conductor/validations/ValidationContext.java