[GORA-372] slf4j-api version conflict

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.6
• Fix Version/s: 0.6
• Component/s: gora-hbase
• Environment: Gentoo Linux, Oracle JDK 1.7.0.51-r1
• Assignee: Viacheslav Dobromyslov
• Reporter: Viacheslav Dobromyslov
• Created: 17/Sep/14 10:50
• Updated: 19/Sep/14 19:15
• Resolved: 19/Sep/14 19:01

Description

Created project with the following dependencies:

    <dependencies>
        <dependency>
            <groupId>org.apache.gora</groupId>
            <artifactId>gora-core</artifactId>
            <version>0.6-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.apache.gora</groupId>
            <artifactId>gora-hbase</artifactId>
            <version>0.6-SNAPSHOT</version>
        </dependency>
    </dependencies>

Snapshot version:
https://github.com/apache/gora/tree/a72c5d36033fa393e492c047cb818b318edd2b35

And got a critical runtime error described below.

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/bbg/.m2/repository/org/slf4j/slf4j-log4j12/1.4.3/slf4j-log4j12-1.4.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/bbg/.m2/repository/org/slf4j/slf4j-simple/1.6.6/slf4j-simple-1.6.6.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: slf4j-api 1.6.x (or later) is incompatible with this binding.
SLF4J: Your binding is version 1.5.5 or earlier.
SLF4J: Upgrade your binding to version 1.6.x.

Stack trace:

Exception in thread "main" java.lang.NoSuchMethodError: org.slf4j.impl.StaticLoggerBinder.getSingleton()Lorg/slf4j/impl/StaticLoggerBinder;
	at org.slf4j.LoggerFactory.bind(LoggerFactory.java:128)
	at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:107)
	at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:295)
	at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:269)
	at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:281)
	at org.apache.gora.tutorial.log.LogManager.<clinit>(LogManager.java:24)

The error is caused by slf4j-api version conflict:

1. gora-hbase depends on org.apache.hbase:hbase-0.94.14
2. hbase-0.94.14 depends on org.slf4j:slf4j-log4j12 which causes the conflict.

We have to exclude this old dependency to sort the issue out.