関連ワード:  check list is null or empty java    check if list is null or empty java 8    check if list is null or empty java 17    check if list is null or empty javascript    check list is not null or empty java    check if collection is null or empty java 8    check collection is null or empty in java    check if list string is null or empty java    java 8 check list is null or empty    best way to check if list is null or empty java