Jetty

SLF4J classes not visible when added as dependencies to maven-jetty-plugin

Details

  • Type: Bug Bug
  • Status: Resolved Resolved
  • Priority: Major Major
  • Resolution: Not A Bug
  • Affects Version/s: 6.1.7, 6.1.8, 6.1.9, 7.0.0pre0, 7.0.0pre1
  • Fix Version/s: 6.1.7
  • Component/s: Maven
  • Labels:
    None
  • Number of attachments :
    1

Description

Adding SLF4J as a dependency to maven-jetty-plugin doesn't make it visible to the running webapp (NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder)
It works fine with other libraries than SLF4J.

Try mvn jetty:run with the attached project.

Activity

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Martin Strand added a comment -

Oops, I mean the error is "NoClassDefFoundError: org/slf4j/LoggerFactory" since it's slf4j-api that isn't visible.

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Martin Strand added a comment - Oops, I mean the error is "NoClassDefFoundError: org/slf4j/LoggerFactory" since it's slf4j-api that isn't visible.
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Igor E. Poteryaev added a comment -

According to Jetty classloading architecture (see http://docs.codehaus.org/display/JETTY/Classloading),
org.slf4j.* classes by default are included in so called ServerClasses and are hidden from webapp context classloaders.

I think that you have two possibilities:

1. Override default ServerClasses list excluding org.slf4j. from it. After it webapp context classloader will see slf4j classes from parent classloader.

or

2. Add slf4j dependencies not only to maven-plugin-jetty, but as dependency at top maven pom <dependencies> level . After it webapp context classloader will see slf4j classes from its own WEB-INF/lib/ directory.

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Igor E. Poteryaev added a comment - According to Jetty classloading architecture (see http://docs.codehaus.org/display/JETTY/Classloading ), org.slf4j.* classes by default are included in so called ServerClasses and are hidden from webapp context classloaders. I think that you have two possibilities: 1. Override default ServerClasses list excluding org.slf4j. from it. After it webapp context classloader will see slf4j classes from parent classloader. or 2. Add slf4j dependencies not only to maven-plugin-jetty, but as dependency at top maven pom <dependencies> level . After it webapp context classloader will see slf4j classes from its own WEB-INF/lib/ directory.
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Martin Strand added a comment -

Sorry for the false alarm, I didn't know Jetty was hiding certain classes.
Your first suggestion works great, I added this to the plugin configuration and now everything's ok:

<configuration>
<webAppConfig>
<contextPath>/test</contextPath>
<serverClasses>
<filter>-org.mortbay.jetty.plus.jaas.</filter>
<filter>org.mortbay.jetty.</filter>
</serverClasses>
</webAppConfig>
</configuration>

Thanks!

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Martin Strand added a comment - Sorry for the false alarm, I didn't know Jetty was hiding certain classes. Your first suggestion works great, I added this to the plugin configuration and now everything's ok: <configuration> <webAppConfig> <contextPath>/test</contextPath> <serverClasses> <filter>-org.mortbay.jetty.plus.jaas.</filter> <filter>org.mortbay.jetty.</filter> </serverClasses> </webAppConfig> </configuration> Thanks!
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Ken Dobson added a comment -

Martin's comment was very helpful to me, but I found that further configuration is required if using jcl-over-slf4j because Jetty exposes the standard Commons Logging API to applications.

Revised configuration:

<webAppConfig>
<contextPath>/test</contextPath>
<serverClasses>
<!-- Copied from WebAppContext with SLF4J removed -->
<filter>-org.mortbay.jetty.plus.jaas.</filter>
<filter>org.mortbay.jetty.</filter>
</serverClasses>
<systemClasses>
<!-- Copied from WebAppContext with Commons Logging and Log4j removed -->
<filter>java.</filter>
<filter>javax.servlet</filter>
<filter>javax.xml.</filter>
<filter>org.mortbay.</filter>
<filter>org.xml.</filter>
<filter>org.w3c.</filter>
</systemClasses>
</webAppConfig>

Apologies for bumping an old, closed bug, but I found this bug when Googling for the problem, and expect this information may be useful to others.

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Ken Dobson added a comment - Martin's comment was very helpful to me, but I found that further configuration is required if using jcl-over-slf4j because Jetty exposes the standard Commons Logging API to applications. Revised configuration: <webAppConfig> <contextPath>/test</contextPath> <serverClasses> <!-- Copied from WebAppContext with SLF4J removed --> <filter>-org.mortbay.jetty.plus.jaas.</filter> <filter>org.mortbay.jetty.</filter> </serverClasses> <systemClasses> <!-- Copied from WebAppContext with Commons Logging and Log4j removed --> <filter>java.</filter> <filter>javax.servlet</filter> <filter>javax.xml.</filter> <filter>org.mortbay.</filter> <filter>org.xml.</filter> <filter>org.w3c.</filter> </systemClasses> </webAppConfig> Apologies for bumping an old, closed bug, but I found this bug when Googling for the problem, and expect this information may be useful to others.
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Fabio Marinelli added a comment -

In reply to Ken comment, there's a missing dot on javax.servlet

This is the working configuration.

<webAppConfig>
<contextPath>/test</contextPath>
<serverClasses>
<!-- Copied from WebAppContext with SLF4J removed -->
<filter>-org.mortbay.jetty.plus.jaas.</filter>
<filter>org.mortbay.jetty.</filter>
</serverClasses>
<systemClasses>
<!-- Copied from WebAppContext with Commons Logging and Log4j removed -->
<filter>java.</filter>
<filter>javax.servlet.</filter>
<filter>javax.xml.</filter>
<filter>org.mortbay.</filter>
<filter>org.xml.</filter>
<filter>org.w3c.</filter>
</systemClasses>
</webAppConfig>

Bye and sorry for posting again on this issue.

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Fabio Marinelli added a comment - In reply to Ken comment, there's a missing dot on javax.servlet This is the working configuration. <webAppConfig> <contextPath>/test</contextPath> <serverClasses> <!-- Copied from WebAppContext with SLF4J removed --> <filter>-org.mortbay.jetty.plus.jaas.</filter> <filter>org.mortbay.jetty.</filter> </serverClasses> <systemClasses> <!-- Copied from WebAppContext with Commons Logging and Log4j removed --> <filter>java.</filter> <filter>javax.servlet.</filter> <filter>javax.xml.</filter> <filter>org.mortbay.</filter> <filter>org.xml.</filter> <filter>org.w3c.</filter> </systemClasses> </webAppConfig> Bye and sorry for posting again on this issue.

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  • Assignee:
    Unassigned
    Reporter:
    Martin Strand
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  • Created:
    Updated:
    Resolved: