Extract column values of Dataframe as List in Apache Spark

Question

I want to convert a string column of a data frame to a list. What I can find from the Dataframe API is RDD, so I tried converting it back to RDD first, and then

Answer 1

List whatever_list = df.toJavaRDD().map(new Function() {
    public String call(Row row) {
        return row.getAs("column_name").toString();
    }
}).collect();

logger.info(String.format("list is %s",whatever_list)); //verification

Since no one has given any solution in java(Real Programming Language) Can thank me later