Hi Mich, Spark 3.4.0 prebuilt with scala 2.13 is built with version 2.13.8. Since you are using spark-core_2.13 and spark-sql_2.13, you should stick to the major(13) and the minor version(8). Not using any of these may cause unexpected behaviour(though scala claims compatibility among minor version changes, I've encountered problem using the scala package with the same major version and different minor version. That may due to bug fixes and upgrade of scala itself.). And although I did not encountered such problem, this can be a a pitfall for you.
Best Regards! ........................................................................... Lingzhe Sun Hirain Technology From: Mich Talebzadeh Date: 2023-05-29 17:55 To: Bjørn Jørgensen CC: user @spark Subject: Re: maven with Spark 3.4.0 fails compilation Thanks for your helpful comments Bjorn. I managed to compile the code with maven but when it run it fails with Application is ReduceByKey Exception in thread "main" java.lang.NoSuchMethodError: scala.package$.Seq()Lscala/collection/immutable/Seq$; at ReduceByKey$.main(ReduceByKey.scala:23) at ReduceByKey.main(ReduceByKey.scala) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.apache.spark.deploy.JavaMainApplication.start(SparkApplication.scala:52) at org.apache.spark.deploy.SparkSubmit.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:1020) at org.apache.spark.deploy.SparkSubmit.doRunMain$1(SparkSubmit.scala:192) at org.apache.spark.deploy.SparkSubmit.submit(SparkSubmit.scala:215) at org.apache.spark.deploy.SparkSubmit.doSubmit(SparkSubmit.scala:91) at org.apache.spark.deploy.SparkSubmit$$anon$2.doSubmit(SparkSubmit.scala:1111) at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:1120) at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala) I attach the pom.xml and the sample scala code is self contained and basic. Again it runs with SBT with no issues. FYI, my scala version on host is scala -version Scala code runner version 2.13.6 -- Copyright 2002-2021, LAMP/EPFL and Lightbend, Inc. I think I have a scala incompatible somewhere again Cheers Mich Talebzadeh, Lead Solutions Architect/Engineering Lead Palantir Technologies Limited London United Kingdom view my Linkedin profile https://en.everybodywiki.com/Mich_Talebzadeh Disclaimer: Use it at your own risk. Any and all responsibility for any loss, damage or destruction of data or any other property which may arise from relying on this email's technical content is explicitly disclaimed. The author will in no case be liable for any monetary damages arising from such loss, damage or destruction. On Sun, 28 May 2023 at 20:29, Bjørn Jørgensen <bjornjorgen...@gmail.com> wrote: From chatgpt4 The problem appears to be that there is a mismatch between the version of Scala used by the Scala Maven plugin and the version of the Scala library defined as a dependency in your POM. You've defined your Scala version in your properties as `2.12.17` but you're pulling in `scala-library` version `2.13.6` as a dependency. The Scala Maven plugin will be using the Scala version defined in the `scala.version` property for compilation, but then it tries to load classes from a different Scala version, hence the error. To resolve this issue, make sure the `scala.version` property matches the version of `scala-library` defined in your dependencies. In your case, you may want to change `scala.version` to `2.13.6`. Here's the corrected part of your POM: ```xml <properties> <maven.compiler.source>1.7</maven.compiler.source> <maven.compiler.target>1.7</maven.compiler.target> <encoding>UTF-8</encoding> <scala.version>2.13.6</scala.version> <!-- Here's the change --> <maven-scala-plugin.version>2.15.2</maven-scala-plugin.version> </properties> ``` Additionally, ensure that the Scala versions in the Spark dependencies match the `scala.version` property as well. If you've updated the Scala version to `2.13.6`, the artifactIds for Spark dependencies should be `spark-core_2.13` and `spark-sql_2.13`. Another thing to consider: your Java version defined in `maven.compiler.source` and `maven.compiler.target` is `1.7`, which is quite outdated and might not be compatible with the latest versions of these libraries. Consider updating to a more recent version of Java, such as Java 8 or above, depending on the requirements of the libraries you're using. The same problem persists in this updated POM file - there's a mismatch in the Scala version declared in the properties and the version used in your dependencies. Here's what you need to update: 1. Update the Scala version in your properties to match the Scala library and your Spark dependencies: ```xml <properties> <maven.compiler.source>1.7</maven.compiler.source> <maven.compiler.target>1.7</maven.compiler.target> <encoding>UTF-8</encoding> <scala.version>2.13.6</scala.version> <!-- updated Scala version --> <maven-scala-plugin.version>2.15.2</maven-scala-plugin.version> </properties> ``` 2. Make sure all your Spark dependencies use the same Scala version. In this case, I see `spark-streaming-kafka_2.11` which should be `spark-streaming-kafka_2.13` if you're using Scala `2.13.6`. ```xml <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-streaming-kafka_2.13</artifactId> <!-- updated to 2.13 --> <version>1.6.3</version> <!-- this might also need to be updated as this is a very old version --> <scope>provided</scope> </dependency> ``` 3. As mentioned in the previous message, your Java version (`maven.compiler.source` and `maven.compiler.target`) is also quite outdated. Depending on the requirements of the libraries you're using, you might want to update this to a newer version, such as Java 8 or above. Finally, ensure that the correct versions of these libraries exist in your Maven repository or are available in the central Maven repository. If the versions don't match, Maven will not be able to find and download the correct dependencies, which can lead to problems. Please note that it's crucial to maintain consistency in your Scala and Java versions across your project and its dependencies to avoid these kinds of issues. Mixing versions can lead to binary incompatibility errors, such as the one you're seeing. The differences in behavior between SBT and Maven when resolving Scala dependencies can be attributed to how they each handle Scala binary versions. SBT is specifically designed for Scala projects and has built-in support for handling Scala's binary compatibility issues. When you define a Scala library dependency in SBT, you can specify the Scala binary version as "_2.12", "_2.13", etc. in the library artifact name. SBT will then automatically replace this with the actual Scala binary version defined in your SBT configuration. So, if you've defined different Scala versions for your project and for a specific dependency, SBT will handle this gracefully. Maven, on the other hand, is more generic and does not have the same level of built-in support for Scala's binary versions. In Maven, the Scala version is typically hardcoded in the artifact name, and if this doesn't match the actual Scala version used in your project, it can lead to binary compatibility issues. This difference between SBT and Maven means that a project can work fine when built with SBT but fail when built with Maven, due to these Scala version discrepancies. To avoid these issues in Maven, you need to ensure that the Scala version is consistent across your project configuration and all your dependencies. Also, another reason for this can be because SBT often fetches dependencies on the fly, while Maven requires them to be explicitly declared. SBT can download and link the correct Scala library version even if it's not explicitly declared, while Maven will only use the versions that have been specified in the POM file. To summarize, SBT is more flexible and Scala-oriented than Maven, which can lead to different behavior when handling Scala dependencies. When using Maven for Scala projects, it's essential to ensure that all Scala versions match across the project. søn. 28. mai 2023 kl. 21:03 skrev Mich Talebzadeh <mich.talebza...@gmail.com>: This compilation works fine with SBT but fails with maven! Spark version 3.4.0 Apache Maven 3.9.2 (c9616018c7a021c1c39be70fb2843d6f5f9b8a1c) Java version: 11.0.1, vendor: Oracle Corporation, runtime: /opt/jdk-11.0.1 This from the pom.xml file <project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>spark</groupId> <version>3.0</version> <name>${project.artifactId}</name> <properties> <maven.compiler.source>1.7</maven.compiler.source> <maven.compiler.target>1.7</maven.compiler.target> <encoding>UTF-8</encoding> <scala.version>2.12.17</scala.version> <maven-scala-plugin.version>2.15.2</maven-scala-plugin.version> </properties> <dependencies> <dependency> <groupId>org.scala-lang</groupId> <artifactId>scala-library</artifactId> <version>2.13.6</version> </dependency> <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-core_2.13</artifactId> <version>3.4.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-sql_2.13</artifactId> <version>3.4.0</version> <scope>provided</scope> The pom file is attached. These are the errors I am getting [ERROR] error: error while loading package, class file '/home/hduser/.m2/repository/org/scala-lang/scala-library/2.13.6/scala-library-2.13.6.jar(scala/reflect/package.class)' is broken [ERROR] (class java.lang.RuntimeException/error reading Scala signature of package.class: Scala signature package has wrong version [ERROR] error: error while loading package, class file '/home/hduser/.m2/repository/org/scala-lang/scala-library/2.13.6/scala-library-2.13.6.jar(scala/package.class)' is broken [ERROR] (class java.lang.RuntimeException/error reading Scala signature of package.class: Scala signature package has wrong version [ERROR] error: error while loading package, class file '/home/hduser/.m2/repository/org/scala-lang/scala-library/2.13.6/scala-library-2.13.6.jar(scala/collection/package.class)' is broken [ERROR] (class java.lang.RuntimeException/error reading Scala signature of package.class: Scala signature package has wrong version [ERROR] three errors found [ERROR] Failed to execute goal org.scala-tools:maven-scala-plugin:2.15.2:compile (default) on project scala: wrap: org.apache.commons.exec.ExecuteException: Process exited with an error: 1(Exit value: 1) -> [Help 1] Any ideas will be appreciated. Mich Talebzadeh, Lead Solutions Architect/Engineering Lead Palantir Technologies Limited London United Kingdom view my Linkedin profile https://en.everybodywiki.com/Mich_Talebzadeh Disclaimer: Use it at your own risk. Any and all responsibility for any loss, damage or destruction of data or any other property which may arise from relying on this email's technical content is explicitly disclaimed. The author will in no case be liable for any monetary damages arising from such loss, damage or destruction. --------------------------------------------------------------------- To unsubscribe e-mail: user-unsubscr...@spark.apache.org -- Bjørn Jørgensen Vestre Aspehaug 4, 6010 Ålesund Norge +47 480 94 297