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maventransitive-dependency

maven - transitive dependencies

I am trying to follow best practices when defining data in pom.xml, so I started to look into the Spring source code, and I have seen:


<project xmlns="http://maven.apache.org/POM/4.0.0"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.springframework</groupId>
  <artifactId>spring-aop</artifactId>
  <packaging>jar</packaging>
  <version>3.1.1.RELEASE</version>
.....

<dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>${project.version}</version>
      <scope>compile</scope>
</dependency>

---

<dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <scope>test</scope>
</dependency>
-----

But, spring-beans also has a dependency on log4j.

Can you please tell me, for the best practice methods, on what extent should you rely on transitive dependencies?

I am asking this because my first thought was not to redeclare the log4j dependency, since spring-beans had already declared it.

Solution

  • Declare dependencies that you explicitly rely on, whether it provides classes you directly import and use or it's something that provides a service you directly use, like Log4J. Transitive dependencies should only supply dependencies that are needed at runtime but that you don't use yourself.