I am getting this following error (Caused by: java.lang.ClassNotFoundException: play.api.libs.functional.syntax.package) while I am trying to run my code I have right dependencies and added right Jar …
Tag: scala
Is it possible to shade some package in only one package in sbt?
let’s consider a following source code: It renames com.google.common and change package names as well. Additionally, thanks to inAll it rewrites all imports and another references in all classes in jar. It works fine. However, the question is: Is it possible to rewrite only chosen references? I mean poi…
How to call Scala curry functions from Java with Generics
A Scala code has a retry mechanism which is based on currying function: object RetryUtil { def retry[T](retry: Int, timeout: FiniteDuration)(exc: => T): T = { // } } I want to call this …
How to get corresponding quarter of previous year in Scala
I have a date string with me in the format – “20202” [“yyyyQ”]. Is there a way to get the corresponding quarter of previous year ? ex- for 20202 , it should be 20192 Answer An alternative to the other answers is using my lib Time4J and its class CalendarQuarter. Example: Two main…
Akka Quickstart: An illegal reflective access operation has occurred
When running the official Akka Quickstart on my Mac terminal, I get this error: Is this the intended result? How can I go about fixing this? Answer This is a warning, not an error. Here is a quote from Oracle JDK 9 Migration Guide https://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG-GUID-7BB28E4D-99B3-4078-…
is scala OpenHashMap remove operator threadsafe
Sorry but I cannot find in the network a direct answer to a very simple questions. is scala OpenHashMap remove operator threadsafe? Regrds. Answer Seems it is not thread safe: Scala OpenHashMap def: Ref link: https://alvinalexander.com/java/jwarehouse/scala-2.11/library/scala/collection/mutable/OpenHashMap.sc…
Apache spark and scala, error while executing queries
I am working with a dataset whose sample is as follows: I have executed the following commands successfully: I am getting following error: java.lang.RuntimeException: Error while encoding: java.lang.RuntimeException: java.lang.Character is not a valid external type for schema of string I am getting the same e…
NoSuchMethodError in shapeless seen only in Spark
I am trying to write a Spark connector to pull AVRO messages off a RabbitMQ message queue. When decoding the AVRO messages, there is a NoSuchMethodError error that occurs only when running in Spark. I could not reproduce the Spark code exactly outside of spark, but I believe the two examples are sufficiently …
how to replace multiple chars efficiently with scala?
I want to replace 5 different chars to 5 different chars, and the current way im doing it looks stupid, so what would be a better way to do this? currently: ? Answer I believe this approach will work for you and takes only one iteration to substitute all characters:
Java Array vs Scala Array
Seems one difference between Java Array and Scala Array is Java Array is co variant. Scala Array is not. Both are mutable. In java, sort method can take different arrays, such as arrays of String or Int. This is often quoted as a good example of Liskov substitution principle. Seems a good design to me? In Sca…