The following code fails and I am wondering how to...

# getting-started

[dirk.dittert]

The following code fails and I am wondering how to make it pass (except from renaming url):

class Example(private val url: String = "jdbc:h2:mem:") {
    val dataSource: DataSource = JdbcDataSource().apply { setUrl(url) }
}

The error message is:

Overload resolution ambiguity between candidates:
var url: String!
var url: String!

The reason for that failure seems to be that the H2 JdbcDataSource class has a private field url. Is there a way to tell the compiler that url should actually reference the value from Example?

[Daniel Pitts]

[e-mail]

[Daniel Pitts]

the other way to do it would be

class Example(private val url: String = "jdbc:h2:mem:") {
    val dataSource: DataSource = JdbcDataSource().also { it.setUrl(url) }
}

[Daniel Pitts]

(Changing apply to also)

[Daniel Pitts]

and a third way:

class Example(private val url: String = "jdbc:h2:mem:") {
    val dataSource: DataSource = JdbcDataSource()
    init {
        dataSource.url = url
    }
}

[dirk.dittert]

Still, it is interesting that there even is a potential conflict (the field url in JdbcDataSource is private)

[Daniel Pitts]

JdbcDataSource is a Java class, and Kotlin will convert the getUrl+setUrl methods into a property. So its not the url field, but the url property that conflicts.

[dirk.dittert]

I missed that there is a getURL() method in the Java class. Knowing that, it makes a lot more sense.

[dirk.dittert]

Thank for for explaining that and for digging into my problem.

[Daniel Pitts]

👍