Team, I am facing one error with my evaluator filter. I included SLFJ-API(1.7.25), logback-core, logback-classic (1.2.3) jars. Also added janino jar (3.1.1). In my logback.xml file belowis what I wrote. <appender name="syslogappender" class="ch.qos.logback.classic.net.SyslogAppender"> <filter class=ch.qos.logback.core.filter.EvaluatorFilter"> <evaluator> <expression> if (level == ERROR && formattedMessage.contains("NullPointerException") ) { return true; } return false; </expression> </evaluator> <onMismatch> NEUTRAL</onMismatch> <onMatch>ACCEPT</onMatch> </filter> </appender> and I amhaving sysloghost, facility and suffixpattern tags as well passed in the above appender. my logger for the above appender is <logger additiity=false level="INFO"> <appender-ref ref=" syslogappender> </logger> <root> <level value="INFO" /> <appender-ref ref="syslogappender" </root> with this above, Iam deploying my app to IBM Mainframe WAS server. During deployment I am getting below error. org.codehaus.commons.compiler.CompileException a class ch.qos.logback.classic.Level could not be found. Please help me how to correct this issue. Thanks.