title: NoSuchMethodError: org.slf4j.spi.LocationAwareLogger.log()
body: <p>I get the following error when starting up my app under Eclipse:</p>
  
  <pre><code>Exception in thread "main" java.lang.NoSuchMethodError: org.slf4j.spi.LocationAwareLogger.log(Lorg/slf4j/Marker;Ljava/lang/String;ILjava/lang/String;[Ljava/lang/Object;Ljava/lang/Throwable;)V
      at org.apache.commons.logging.impl.SLF4JLocationAwareLog.info(SLF4JLocationAwareLog.java:159)
      at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:273)
      at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
      at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:782)
      at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:424)
      at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:774)
      at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:249)
      at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1242)
      at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:717)
      at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:494)
      at com.google.gwt.dev.shell.jetty.JettyLauncher$WebAppContextWithReload.doStart(JettyLauncher.java:541)
      at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
      at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95)
      at org.eclipse.jetty.server.handler.RequestLogHandler.doStart(RequestLogHandler.java:162)
      at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
      at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95)
      at org.eclipse.jetty.server.Server.doStart(Server.java:282)
      at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
      at com.google.gwt.dev.shell.jetty.JettyLauncher.start(JettyLauncher.java:740)
      at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:632)
      at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1054)
      at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:836)
      at com.google.gwt.dev.DevMode.main(DevMode.java:413)
     Ignored 39 units with compilation errors in first pass.
  </code></pre>
  
  <p>Here is the dependency tree generated by Maven:</p>
  
  <pre><code>[INFO] com.kn.mik.mobile:GandEMobile:war:0.0.1-SNAPSHOT
  [INFO] +- com.kn.mik:GandE:jar:0.0.1-SNAPSHOT:compile
  [INFO] |  +- postgresql:postgresql:jar:9.1-901-1.jdbc4:compile
  [INFO] |  +- com.google.code.gson:gson:jar:2.3.1:compile
  [INFO] |  +- com.kn.knt:sconsole:jar:0.0.1-SNAPSHOT:compile
  [INFO] |  |  +- com.kn.knt:baseuser:jar:0.0.1-SNAPSHOT:compile
  [INFO] |  |  |  \- org.jasypt:jasypt:jar:1.9.0:compile
  [INFO] |  |  +- com.kn.knt:baseuser:jar:sources:0.0.1-SNAPSHOT:compile
  [INFO] |  |  +- org.apache.velocity:velocity:jar:1.7:compile
  [INFO] |  |  +- com.kn:integrity:jar:0.0.1-SNAPSHOT:compile
  [INFO] |  |  +- com.kn:integrity:jar:sources:0.0.1-SNAPSHOT:compile
  [INFO] |  |  +- com.kn.knt:kntcore:jar:0.0.1-SNAPSHOT:compile
  [INFO] |  |  |  +- javax.mail:mail:jar:1.4:compile
  [INFO] |  |  |  +- commons-lang:commons-lang:jar:2.3:compile
  [INFO] |  |  |  +- commons-collections:commons-collections:jar:3.2.1:compile
  [INFO] |  |  |  +- net.sf.dozer:dozer:jar:5.2.0:compile
  [INFO] |  |  |  |  +- commons-logging:commons-logging:jar:1.1.1:compile
  [INFO] |  |  |  |  \- commons-beanutils:commons-beanutils:jar:1.8.0:compile
  [INFO] |  |  |  +- joda-time:joda-time:jar:2.2:compile
  [INFO] |  |  |  +- joda-time:joda-time-hibernate:jar:1.3:compile
  [INFO] |  |  |  +- com.github.nmorel.gwtjackson:gwt-jackson:jar:0.10.0:compile
  [INFO] |  |  |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.6.1:compile
  [INFO] |  |  |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:sources:2.6.1:compile
  [INFO] |  |  |  |  \- com.squareup:javapoet:jar:1.0.0:compile
  [INFO] |  |  |  \- org.jadira.usertype:usertype.core:jar:3.1.0.CR1:compile
  [INFO] |  |  |     \- org.jadira.usertype:usertype.spi:jar:3.1.0.CR1:compile
  [INFO] |  |  +- com.kn.knt:kntcore:jar:sources:0.0.1-SNAPSHOT:compile
  [INFO] |  |  +- org.springframework.security:org.springframework.security.web:jar:3.0.3.RELEASE:compile
  [INFO] |  |  |  \- org.apache.commons:com.springsource.org.apache.commons.logging:jar:1.1.1:compile
  [INFO] |  |  +- org.springframework.security:org.springframework.security.core:jar:3.0.3.RELEASE:compile
  [INFO] |  |  |  \- org.aopalliance:com.springsource.org.aopalliance:jar:1.0.0:compile
  [INFO] |  |  +- org.springframework:org.springframework.jms:jar:3.2.3.RELEASE:compile
  [INFO] |  |  |  +- org.springframework:org.springframework.oxm:jar:3.2.3.RELEASE:compile
  [INFO] |  |  |  +- org.codehaus.jackson:com.springsource.org.codehaus.jackson.mapper:jar:1.4.2:compile
  [INFO] |  |  |  |  \- org.codehaus.jackson:com.springsource.org.codehaus.jackson:jar:1.4.2:compile
  [INFO] |  |  |  \- com.fasterxml.jackson.core:com.springsource.com.fasterxml.jackson.core.jackson-core:jar:2.0.2:compile
  [INFO] |  |  +- org.springframework:org.springframework.core:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.web:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.aspects:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.beans:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.transaction:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.orm:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.jdbc:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.web.servlet:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.context:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.aop:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- org.springframework:org.springframework.expression:jar:3.2.3.RELEASE:compile
  [INFO] |  |  +- commons-fileupload:commons-fileupload:jar:1.2.2:compile
  [INFO] |  |  +- org.hibernate:hibernate-entitymanager:jar:4.1.4.Final:compile
  [INFO] |  |  |  +- org.jboss.logging:jboss-logging:jar:3.1.0.GA:compile
  [INFO] |  |  |  +- org.hibernate:hibernate-core:jar:4.1.4.Final:compile
  [INFO] |  |  |  |  \- antlr:antlr:jar:2.7.7:compile
  [INFO] |  |  |  +- org.jboss.spec.javax.transaction:jboss-transaction-api_1.1_spec:jar:1.0.0.Final:compile
  [INFO] |  |  |  +- dom4j:dom4j:jar:1.6.1:compile
  [INFO] |  |  |  +- org.hibernate.javax.persistence:hibernate-jpa-2.0-api:jar:1.0.1.Final:compile
  [INFO] |  |  |  +- org.javassist:javassist:jar:3.15.0-GA:compile
  [INFO] |  |  |  \- org.hibernate.common:hibernate-commons-annotations:jar:4.0.1.Final:compile
  [INFO] |  |  +- org.hibernate:hibernate-validator-annotation-processor:jar:4.1.0.Final:compile
  [INFO] |  |  |  \- org.hibernate:hibernate-validator:jar:4.1.0.Final:compile
  [INFO] |  |  \- commons-net:commons-net:jar:2.2:compile
  [INFO] |  +- com.kn.knt:sconsole:jar:sources:0.0.1-SNAPSHOT:compile
  [INFO] |  +- com.kn.knt:audit:jar:0.0.1-SNAPSHOT:compile
  [INFO] |  \- commons-io:commons-io:jar:2.4:compile
  [INFO] +- com.kn.mik:GandE:jar:sources:0.0.1-SNAPSHOT:provided
  [INFO] +- javax.xml:jaxrpc-api:jar:1.1:compile
  [INFO] |  \- javax.xml.soap:saaj-api:jar:1.3:compile
  [INFO] |     \- javax.activation:activation:jar:1.1:compile
  [INFO] +- com.google.gwt:gwt-servlet:jar:2.7.0:provided
  [INFO] +- com.google.gwt:gwt-user:jar:2.7.0:provided
  [INFO] |  +- javax.validation:validation-api:jar:1.0.0.GA:compile
  [INFO] |  \- javax.validation:validation-api:jar:sources:1.0.0.GA:provided
  [INFO] +- com.google.gwt:gwt-codeserver:jar:2.7.0:provided
  [INFO] |  \- com.google.gwt:gwt-dev:jar:2.7.0:provided
  [INFO] |     +- org.ow2.asm:asm:jar:5.0.3:provided
  [INFO] |     +- org.ow2.asm:asm-util:jar:5.0.3:provided
  [INFO] |     |  \- org.ow2.asm:asm-tree:jar:5.0.3:provided
  [INFO] |     \- org.ow2.asm:asm-commons:jar:5.0.3:provided
  [INFO] +- com.sksamuel.jqm4gwt:jqm4gwt-library:jar:1.5.0-SNAPSHOT:provided
  [INFO] +- com.sksamuel.jqm4gwt:jqm4gwt-datebox:jar:1.5.0-SNAPSHOT:provided
  [INFO] +- com.sksamuel.jqm4gwt:jqm4gwt-datatables:jar:1.5.0-SNAPSHOT:compile
  [INFO] +- junit:junit:jar:4.11:test
  [INFO] |  \- org.hamcrest:hamcrest-core:jar:1.3:test
  [INFO] +- org.slf4j:slf4j-api:jar:1.6.1:compile
  [INFO] +- org.slf4j:slf4j-log4j12:jar:1.6.1:compile
  [INFO] |  \- log4j:log4j:jar:1.2.16:compile
  [INFO] \- kn.sso:SSOIntegrationWebCommon:jar:1.14.90:compile
  [INFO]    +- org.springframework.security.extensions:spring-security-saml2-core:jar:1.0.1.RELEASE:compile
  [INFO]    |  +- org.opensaml:opensaml:jar:2.6.1:compile
  [INFO]    |  |  +- org.opensaml:openws:jar:1.5.1:compile
  [INFO]    |  |  |  +- org.opensaml:xmltooling:jar:1.4.1:compile
  [INFO]    |  |  |  |  +- org.bouncycastle:bcprov-jdk15:jar:1.46:compile
  [INFO]    |  |  |  |  \- ca.juliusdavies:not-yet-commons-ssl:jar:0.3.9:compile
  [INFO]    |  |  |  +- commons-httpclient:commons-httpclient:jar:3.1:compile
  [INFO]    |  |  |  \- org.apache.santuario:xmlsec:jar:1.5.6:compile
  [INFO]    |  |  +- commons-codec:commons-codec:jar:1.7:compile
  [INFO]    |  |  +- org.owasp.esapi:esapi:jar:2.0.1:compile
  [INFO]    |  |  +- xerces:xercesImpl:jar:2.10.0:runtime
  [INFO]    |  |  +- xalan:serializer:jar:2.7.1:runtime
  [INFO]    |  |  +- xml-resolver:xml-resolver:jar:1.2:runtime
  [INFO]    |  |  \- xalan:xalan:jar:2.7.1:runtime
  [INFO]    |  +- org.springframework.security:spring-security-config:jar:3.2.9.RELEASE:compile
  [INFO]    |  |  +- aopalliance:aopalliance:jar:1.0:compile
  [INFO]    |  |  +- org.springframework:spring-aop:jar:3.2.13.RELEASE:compile
  [INFO]    |  |  +- org.springframework:spring-beans:jar:3.2.13.RELEASE:compile
  [INFO]    |  |  +- org.springframework:spring-context:jar:3.2.13.RELEASE:compile
  [INFO]    |  |  \- org.springframework:spring-core:jar:3.2.13.RELEASE:compile
  [INFO]    |  +- org.springframework.security:spring-security-core:jar:3.1.2.RELEASE:compile
  [INFO]    |  |  \- org.springframework:spring-expression:jar:3.0.7.RELEASE:compile
  [INFO]    |  +- org.springframework.security:spring-security-web:jar:3.2.9.RELEASE:compile
  [INFO]    |  |  \- org.springframework:spring-web:jar:3.2.13.RELEASE:compile
  [INFO]    |  \- xml-apis:xml-apis:jar:1.4.01:runtime
  [INFO]    \- org.slf4j:jcl-over-slf4j:jar:1.6.1:runtime
  </code></pre>
  
  <p>Obviously I have a clash between the logging jars but I have tried to find out which one is causing the problem but without success.  Any hints or pointers gratefully received.</p>