Creating a Java Object in Scala

Question

I have a Java class "Listings". I use this in my Java MapReduce job as below:

public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
Listings le = new Listings(value.toString());
...
}

I want to run the same job on Spark. So, I am writing this in Scala now. I imported the Java class:

import src.main.java.lists.Listings

I want to create a Listings object in Scala. I am doing this:

val file_le = sc.textFile("file// Path to file")
Listings lists = new Listings(file_le)

I get an error:

value lists is not a member of object src.main.java.lists.Listings

What is the right way to do this?

Never worked on Scala. That being said, try changing the import to import lists.Listings — Chetan Kinger
– Chetan Kinger, Commented Mar 9, 2015 at 17:29
Thanks @bot . Import works fine. The next line is what I am talking about. — spark_user
– spark_user, Commented Mar 9, 2015 at 17:37

childofsoong · Accepted Answer · 2015-03-09 18:00:40Z

4

Based on what you've said, I think you may be forgetting the differences between Scala syntax and Java syntax.

Try this:

val lists: Listings = new Listings(SomeString)

Please note that specifying the type in Scala is completely optional. Also, use a var if you're going to be changing the value of lists.

The way you have it, Scala is trying to interpret it by its ability to call methods/access values of an object without the '.', so you're actually telling Scala this:

Listings.lists = new Listings(SomeString)

answered Mar 9, 2015 at 18:00

childofsoong

1,95617 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

spark_user Over a year ago

Thanks @soong . Now I get this error: error: overloaded method constructor Listings with alternatives: (x$1: String)src.main.java.lists.Listings. cannot be applied to (org.apache.spark.rdd.RDD[String])

childofsoong Over a year ago

I'm afraid I'm not entirely certain how to fix that part, as my knowledge on using Java from within Scala is rather limited. Doing a bit of research, it sounds like it has something to do with the parameterized types in use. These links might help you, though you might want to ask a second question. stackoverflow.com/questions/8041105/… stackoverflow.com/questions/6735698/…

spark_user Over a year ago

Thank you @soong. I did Listings lists = new Listings(file_le.toString). Now I get ArrayIndexOutOfBoundsException: 1. I get the same error when I try to pass any string. What could be wrong?

spark_user Over a year ago

Yes. Not toString. Sorry. Used mkString. I get java.lang.ArrayIndexOutOfBoundsException: 1 error

spark_user Over a year ago

I was splitting the input using a wrong character. I got it working! val lists: Listings = new Listings(SomeString) works now.

Collectives™ on Stack Overflow

Creating a Java Object in Scala

1 Answer 1

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related