We can see that there are different versions of the same dependency in the tree. For example, there are two versions of the spring-beans dependency: 5. Maven has resolved this version conflict, but how?
What does omitted for duplicate and omitted for conflict mean? For example, if we have two versions 1. Other version values can be 1. Second, Maven takes the approach of the nearest transitive dependency in the tree depth and the first in resolution. We start with a POM file having some dependencies with transitive dependencies to make it short, all the dependencies will be represented by the letter D :.
Note that each of the direct dependencies pulls in a different version of the DT dependency. Maven will create a dependency tree and following the criteria mentioned above, a dependency will be selected for DT :.
We note that the resolution order played a major role in choosing the DT dependency since the v1. So even if v1. If we wanted to use version v1. In this case, v1. So, to help us understand the dependency tree result from above, Maven indicates for each transitive dependency why it was omitted:. Now it is clear for us how Maven resolves transitive dependencies. For some reason, we may be tempted one day to pick a specific version of a dependency and get rid of all the processes made by Maven to select it.
To do this we have two options:. If we want to resolve a dependency conflict ourselves, we have to tell Maven which version to choose. There are two ways of doing this. Adding the desired transitive dependency version as a direct dependency in the POM file will result in making it the nearest in depth. This way Maven will select this version.
In our previous example, if we wanted version v1. For projects with sub-modules, to ensure compatibility and coherence between all the modules, we need a way to provide the same version of a dependency across all sub-modules. For this, we can use the dependencyManagement section: it provides a lookup table for Maven to help determine the selected version of a transitive dependency and to centralize dependency information. A dependencyManagement section contains dependency elements.
Each dependency is a lookup reference for Maven to determine the version to select for transitive and direct dependencies. Support for Scala 2. For more information on migrating from Scala 2.
Notice that you need repository credentials to resolve dependencies. For Scala 2. We recommend including the BOM files as a parent because the files contain a plugin management section and useful properties. You need to upload this fat JAR to the Workspace before you run the application in the cloud. The shading mechanism is required because of a conflict between the version of the protobuf-java library used in Apache Flink and Apache Spark, and the version of this library used by Data SDK libraries and Protobuf layer schemas.
If you cannot include the files as parent into your POM, check the content of the files, copy properties, and plugin management configuration which are relevant for your projects. As soon as your project includes a BOM file, the project can reference a Data SDK library or dependency without specifying the actual version of the library.
This approach simplifies migration from one Data SDK version to a newer one. This approach simplifies the migration from one Data SDK version to a more recent one. When an application which depends on a different version of a package is defined in the BOM, it may see runtime exceptions such as the following:. These exceptions are raised when classes or methods are not found in the library provided in the runtime environment.
There are two common cases:. If the library is referenced in your project, you can use a corresponding version of the library from the BOM files. However, the version of one of the transitive dependencies may have a conflict with the version provided in the runtime environment. In this case, you need to shade this transitive dependency. This profile shades the protobuf-java package as mentioned earlier. Only the Maven build system supports these archetypes. Each pipeline job is executed within a specific runtime environment.
This environment consists of the following:. A batch Spark or streaming Flink environment comes with a list of packages that are loaded by the Java Virtual Machine JVM and take precedence over any other application-provided package.
Packages for a runtime environment are marked as provided in the corresponding environment BOM. For example, the Apache Spark package spark-core is marked as provided in environment-batch For more information about the libraries provided by the pipeline runtime environments, see the corresponding environment POM files. The schemas are stored in a special repository which requires platform credentials. To include a schema artifact shared with you in your project when you have one of the plugins configured, follow the steps below.
McDowell McDowell k 29 29 gold badges silver badges bronze badges. Interesting tip. I never thought of that. Luckily, merging XML files is not that common. You should never merge XML files as simple text files. Every XML file should start with a prolog. BOMInputStream Javadocs: This class detects these bytes and, if required, can automatically skip them and return the subsequent byte as the first byte in the stream. Robert Fleming Robert Fleming 1, 17 17 silver badges 13 13 bronze badges.
Matt - I copied the description from the Javadocs. Hope that helps. Sign up or log in Sign up using Google. Sign up using Facebook.
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