Whether module `acl` can compatible with 1.6 as same as module `client`

[geektao]

when use client with acl to connect broker, it will throw compatibility exception，as follows：
java.lang.UnsupportedClassVersionError: org/apache/rocketmq/acl/common/AclClientRPCHook : Unsupported major.minor version 52.0.
I read the latest(4.5.2) client version's pom.xml,it compile with 1.6 . but module ‘acl’ inherit parent java version is 1.8.

Whether module acl can compatible with 1.6 as same as module client?

[duhenglucky]

@geektao good question, would you like to pull a request to change the ACL client dependency to 1.6? add the maven property in pom.xml
<maven.compiler.source>1.6</maven.compiler.source>
<maven.compiler.target>1.6</maven.compiler.target>

and modify relative errors led by this change, more errors maybe the Map or List definition.