java8 use Lambda expressions transfer list

List<PackageCourse> packageCourseList = packageCourseList.stream().filter(v -> v.getCourse()!=null).collect(Collectors.toList());

Explanation:

Recount into a getCourse ()! = Null the list collection.

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List<CourseBuyRecord> filterList = recordList.stream().filter((v) -> !memberMap.containsKey(v.getCourseId())).collect(Collectors.toList());

Explanation:

Recount to list a collection of key memberMap not included in CourseBuyRecord.getCourseId () of.