About "HADOOP_CLASSPATH" environment variable

• https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/UnixShellGuide.html#HADOOP_CLASSPATH

In Hadoop ecosystem, HADOOP_CLASSPATH environment variable is commonly used in many places. Hive is use this variable, too. I wonder that how the HADOOP_CLASSPATH variable is used in a script like beeline. I cannot find HADOOP_CLASSPATH variable in Hive source codes. I finally figure out that when executing beeline it uses hadoop jar command. (https://github.com/apache/hive/blob/rel/release-3.1.3/bin/ext/beeline.sh#L35) It uses RunJar.java where HADOOP_CLASSPATH is used to set CLASSPATH. (https://github.com/apache/hadoop/blob/rel/release-3.3.4/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/RunJar.java#L347-L351)

If something in Hadoop ecosystem uses RunJar#main, it probably repect HADOOP_CLASSPATH environment variable.