Logstash conf for java stacktraces

logtash.conf

input {
    file {
        type => "tomcat"
        path => ["/var/logs/*"]
        codec => multiline {
            pattern => "(^.+Exception: .+)|(^\s+at .+)|(^\s+... \d+ more)|(^\s*Caused by:.+)|(^\s+...\s[\d]+[\s\w]+$)"
            what => "previous"
        }
    }
}

filter {
    if [type] == "tomcat" and "multiline" in [tags] {
        grok {
            match => ["message", "%{JAVASTACKTRACEPART}"]
        }
    }
}
output {
    stdout {
        codec => rubydebug
    }
}