improve dockerfile

build/Dockerfile

@@ -1,36 +1,26 @@
 FROM maven:3.8.5-openjdk as javabuilder
 
-RUN mkdir /opt/jmx_exporter
-COPY . /opt/jmx_exporter
-WORKDIR /opt/jmx_exporter/
+WORKDIR /opt/jmx_exporter
+COPY . .
 RUN mvn package -DskipTests
 
-FROM anapsix/alpine-java:9 as scratch
-
-RUN apk update && apk upgrade && apk --update add curl && rm -rf /tmp/* /var/cache/apk/*
-
-ENV VERSION 0.20.1
-ENV JAR jmx_prometheus_httpserver-$VERSION.jar
-COPY --from=javabuilder /opt/jmx_exporter/jmx_prometheus_httpserver/target/jmx_prometheus_httpserver-$VERSION-SNAPSHOT.jar /opt/jmx_exporter/$JAR
-COPY build/start.sh /opt/jmx_exporter
-COPY build/config.yml /opt/jmx_exporter
-RUN chmod +x /opt/jmx_exporter/start.sh
-
-CMD ["/opt/jmx_exporter/start.sh"]
-
 FROM quay.io/sysdig/sysdig-mini-ubi:1.5.8 as ubi
-RUN mkdir -p /opt/jmx_exporter
+
 RUN microdnf --assumeyes --disableplugin=subscription-manager --nodocs update && \
     microdnf --assumeyes --disableplugin=subscription-manager --nodocs install curl java-1.8.0-openjdk && \
     microdnf --assumeyes --disableplugin=subscription-manager --nodocs clean all && \
     rm -rf /usr/lib/python3.6 && \
     rm -rf /var/cache/yum
+
 ENV VERSION 0.20.1
 ENV JAR jmx_prometheus_httpserver-$VERSION.jar
+
 COPY --from=javabuilder /opt/jmx_exporter/jmx_prometheus_httpserver/target/jmx_prometheus_httpserver-$VERSION-SNAPSHOT.jar /opt/jmx_exporter/$JAR
 COPY --chown=sysdig:sysdig build/start.sh /opt/jmx_exporter
 COPY --chown=sysdig:sysdig build/config.yml /opt/jmx_exporter
+
 RUN chmod +x /opt/jmx_exporter/start.sh
+
 USER sysdig:sysdig
 
 CMD ["/opt/jmx_exporter/start.sh"]