strange thing about eclipse and maven, and eclipse's auto build

Question

I use STS and it's a spring web project.

when i run maven build manually, shows:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".

but this project still can auto build and deploy to tomcat

so Does the eclipse use maven to build my project when i save file and use auto build

Answer 1

First of all. Regarding the dependencies.

I am covering this aspect in case you have forgoten to add the required dependecy.

In order to add SLF4J you must put ONE and only ONE of these dependencies in your pom.xml. It depends on what implementation you choose to use. Every dependency you add in the pom.xml is added automatically in the classpath. If one of the below dependencies are provided by another dependency then you can omit it. Dont forget that you must include only one even if the dependency is provided by another dependency. Notice that i have omitted the version from the dependencies. Use the latest available.

<dependency>
   <groupId>ch.qos.logback</groupId>
   <artifactId>logback-classic</artifactId>
   <version></version>
</dependency>

<dependency>
   <groupId>org.slf4j</groupId>
   <artifactId>slf4j-simple</artifactId>
   <version></version>
   <scope>compile</scope>
</dependency>

<dependency>
   <groupId>org.slf4j</groupId>
   <artifactId>slf4j-log4j12</artifactId>
   <version></version>
   <scope>compile</scope>
</dependency>

<dependency>
   <groupId>org.slf4j</groupId>
   <artifactId>slf4j-jdk14</artifactId>
   <version></version>
   <scope>compile</scope>
</dependency>

---

Regarding the annoying error

If after having only one of the above dependencies you still get the SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". then you are facing a bug from m2e.

Eclipse Juno and Indigo, when using the bundled maven version(m2e), are not suppressing the message SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". This behaviour is present from the m2e version 1.1.0.20120530-0009 and onwards.

Although, this is indicated as an error your logs will be saved normally. The highlighted error will still be present until there is a fix of this bug. More about this in the m2e support site.

The current available solution is to use an external maven version rather than the bundled version of Eclipse. You can find about this solution and more details regarding this bug in the question below which i think describes the same problem you are facing.

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". error

Answer 2

You need to make sure at least on binding implementation of slf4j is in your classpath, i.e:

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>1.7.5</version>
 </dependency>

Answer 3

You need to add the dependency of implementation of slf4j to you pom.xml , such as slf4j-nop.