" Object java.lang.String not a value" error in scala code

Question

I have the below piece of code in my scala program that uses Flink's Table API.

val custTS = new CsvTableSource("D:\\input\\customerinfo.csv", 
                               Array("customerId","name","address","zip"),
                               Array(String,String,String,Long))

The editor is displaying error at the third line for the three 'String's with the error message "Object java.lang.String not a value". 'String' is used in many other places in the rest of the code. But it doesn't throw error anywhere else. I saw a couple of Stackoverflow questions with similar issues mentioned, but I couldn't fix this based on the solutions mentioned. The imports in the program are given below.

import org.apache.flink.api.scala._
import org.apache.flink.table.api.TableEnvironment
import org.apache.flink.table.api.scala._
import org.apache.flink.table.sinks.CsvTableSink
import org.apache.flink.table.sources.CsvTableSource

I have used 'String' in many other scala programs for Flink. But I haven't encountered such an error in any of those programs.

Dawid Wysakowicz · Accepted Answer · 2017-03-24 09:16:31Z

2

First of all you can't use types (in this case String) as a value in Array. Collections stores objects. You should pass array of type Array[TypeInformation[_]].

So it should look like:

import org.apache.flink.table.api.Types

val custTS = new CsvTableSource(
  "D:\\input\\customerinfo.csv",
  Array("customerId", "name", "address", "zip"),
  Array[TypeInformation[_]](Types.STRING, Types.STRING, Types.STRING, Types.LONG)
  )

Unfortunately right now you have to explicitly provide type for the Array. For reasons why, you can have a look at this discussion.

edited Mar 24, 2017 at 9:16

answered Mar 24, 2017 at 9:10

Dawid Wysakowicz

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1 Comment

avidlearner Over a year ago

Thank you Dawid. That solved the problem. In the previous code, I had used the code snippet from the link "slideshare.net/fhueske/…" as my reference. But I guess they were supposed to be guidelines and not to be used directly in the code.

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