[FELIX-2492] scr plugin: using src annotations causes NoClassDefFoundError and other errors

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: maven-scr-plugin-1.4.4
• Fix Version/s: maven-scr-plugin-1.7.2, scr ant task 1.1.2, scr generator 1.1.2
• Component/s: SCR Tooling
• Assignee: Carsten Ziegeler
• Reporter: Michael Dürig
• Created: 29/Jul/10 09:18
• Updated: 05/May/20 08:15
• Resolved: 07/Jun/11 10:03

Description

Using comment tags and having a dependency on slf4j-api causes the scr plugin to throw a NoClassDefFoundError:

java.lang.NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder
at org.slf4j.LoggerFactory.<clinit>(LoggerFactory.java:60)
at com.day.crx.spi.sharepoint.resource.SharepointResourceProvider.<clinit>(SharepointResourceProvider.java:60)
at sun.misc.Unsafe.ensureClassInitialized(Native Method)
at sun.reflect.UnsafeFieldAccessorFactory.newFieldAccessor(UnsafeFieldAccessorFactory.java:25)
at sun.reflect.ReflectionFactory.newFieldAccessor(ReflectionFactory.java:122)
at java.lang.reflect.Field.acquireFieldAccessor(Field.java:918)
at java.lang.reflect.Field.getFieldAccessor(Field.java:899)
at java.lang.reflect.Field.get(Field.java:358)
at org.apache.felix.scrplugin.tags.ClassUtil.getInitializationExpression(ClassUtil.java:41)
at org.apache.felix.scrplugin.tags.qdox.QDoxJavaField.getInitializationExpression(QDoxJavaField.java:44)
at org.apache.felix.scrplugin.helper.PropertyHandler.getPropertyName(PropertyHandler.java:239)

A workaround is to add a 'dummy' dependency to i.e. slf4j-simple. But then

[WARNING] Unused declared dependencies found:
[WARNING] org.slf4j:slf4j-simple:jar:1.5.0:provided

Furthermore when the 'dummy' dependency has the wrong version, the scr plugin might throw other errors:

java.lang.NoSuchFieldError: name
at org.slf4j.impl.Log4jLoggerAdapter.<init>(Log4jLoggerAdapter.java:75)
at org.slf4j.impl.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:75)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:103)
at com.day.crx.spi.sharepoint.resource.SharepointResourceProvider.<clinit>(SharepointResourceProvider.java:60)
at sun.misc.Unsafe.ensureClassInitialized(Native Method)
at sun.reflect.UnsafeFieldAccessorFactory.newFieldAccessor(UnsafeFieldAccessorFactory.java:25)
at sun.reflect.ReflectionFactory.newFieldAccessor(ReflectionFactory.java:122)
at java.lang.reflect.Field.acquireFieldAccessor(Field.java:918)
at java.lang.reflect.Field.getFieldAccessor(Field.java:899)
at java.lang.reflect.Field.get(Field.java:358)
at org.apache.felix.scrplugin.tags.ClassUtil.getInitializationExpression(ClassUtil.java:41)
at org.apache.felix.scrplugin.tags.qdox.QDoxJavaField.getInitializationExpression(QDoxJavaField.java:44)
at org.apache.felix.scrplugin.helper.PropertyHandler.getPropertyName(PropertyHandler.java:238)

I think such errors should be handled more gracefully indicating the source of the problem. Also it should not be necessary to have a 'dummy' dependencies. This was not the case up to version 1.4.1.
If it is absolutely necessary to include such dummy dependencies, the plugin should state so in its error message. Also the slf4j case is so common that it might be worth to considering a specific solution/workaround for this in the plugin. This is still much better than forcing all clients to analyze the problem from the stacktrace and then implement workarounds.

Issue Links

• duplicates: FELIX-1726 SCR Annotations - Enhance error messages in case of missing project dependencies
• is related to: JCR-4562 Remove workaround for FELIX-2492