improve

Author: fey

Dockerfile

@@ -1,20 +1,24 @@
 FROM hexletbasics/base-image:latest
 
-WORKDIR /exercises-java
+ENV COURSE_DIR=/exercises-java
 
-ENV PATH=/exercises-java/bin:$PATH
+WORKDIR ${COURSE_DIR}
 
-RUN apt-get update && apt-get install -yqq openjdk-21-jdk
+ENV PATH=${COURSE_DIR}/bin:$PATH
 
-ENV CHECKSTYLE_VERSION 10.22.0
+RUN apt-get update && apt-get install -yqq openjdk-21-jdk \
+  && rm -rf /var/lib/apt/lists/*
+
+ENV CHECKSTYLE_VERSION=10.22.0
 RUN curl -L https://github.com/checkstyle/checkstyle/releases/download/checkstyle-${CHECKSTYLE_VERSION}/checkstyle-${CHECKSTYLE_VERSION}-all.jar > /opt/checkstyle.jar
 RUN chmod 777 /opt/checkstyle.jar
 
-ENV ASSERTJ_VERSION 3.24.2
+ENV ASSERTJ_VERSION=3.24.2
+
 RUN curl -L https://repo1.maven.org/maven2/org/assertj/assertj-core/${ASSERTJ_VERSION}/assertj-core-${ASSERTJ_VERSION}.jar > /opt/assertj.jar
 RUN chmod 777 /opt/assertj.jar
 
-ENV COMMONS_LANG3_VERSION 3.14.0
+ENV COMMONS_LANG3_VERSION=3.14.0
 RUN curl -L https://repo1.maven.org/maven2/org/apache/commons/commons-lang3/${COMMONS_LANG3_VERSION}/commons-lang3-${COMMONS_LANG3_VERSION}.jar > /opt/commons_lang3.jar
 RUN chmod 777 /opt/commons_lang3.jar