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jdbcsnowflake-cloud-data-platform

Any snowflake-jdbc query throws NullPointerException: Cannot invoke "java.util.List.size()" because "this.currentConverters" is null

I'm trying to execute a simple JDBC query against a Snowflake database, just to test the connectivity.

In my pom,

<dependencies>
    <!-- https://mvnrepository.com/artifact/net.snowflake/snowflake-jdbc -->
    <dependency>
        <groupId>net.snowflake</groupId>
        <artifactId>snowflake-jdbc</artifactId>
        <version>3.15.0</version>
    </dependency>
</dependencies>

I can successfully create a connection. My credentials are accepted as valid. However, even the simplest of queries results in an NPE thrown from within the net.snowflake.client package.

val connection = DriverManager.getConnection(dbUrl, connectionProperties)

connection.prepareStatement("select 1")
          .executeQuery()
          .getInt(1)

Executing this results in the following error:

java.lang.NullPointerException: Cannot invoke "java.util.List.size()" because "this.currentConverters" is null
  at net.snowflake.client.jdbc.ArrowResultChunk$ArrowChunkIterator.getCurrentConverter(ArrowResultChunk.java:462)
  at net.snowflake.client.core.SFArrowResultSet.getInt(SFArrowResultSet.java:408)
  at net.snowflake.client.jdbc.SnowflakeResultSetV1.getInt(SnowflakeResultSetV1.java:192)

I'm dumbfounded that my "hello world" program resulted in an internal error in the library.

Surely there must be a way to solve this? Am I missing some other dependency, maybe?

Solution

  • Silly me, I forgot to call next before using the result set.

    I took a look at the ArrowResultChunk code, and it turns out that currentConverters is not initialized until ResultSet::next is called.

    So, here is a working version of the above code (with auto closing resources too)

    connection.prepareStatement("select 1").use { ps ->
    ps.executeQuery().use { rs ->
        rs.next()
        rs.getInt(1)
    }
}