Adding support for Cassandra 4 and java 11.

.circleci/config.yml

diff --git a/.circleci/config.yml b/.circleci/config.yml
index a7401a5..c5cd3c6 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -5,7 +5,7 @@
 version: 2.1
 
 aliases:
-  base_job: &base_job
+  base_job8: &base_job8
     docker:
       # specify the version you desire here
       - image: circleci/openjdk:8-jdk
@@ -15,6 +15,16 @@
     environment:
       TERM: dumb
 
+  base_job11: &base_job11
+    docker:
+      # specify the version you desire here
+      - image: circleci/openjdk:11-jdk
+
+    working_directory: ~/repo
+
+    environment:
+      TERM: dumb
+
 commands:
   install_ccm:
     description: "Installs and starts CCM"
@@ -74,8 +84,8 @@
 
 jobs:
 
-  build:
-    <<: *base_job
+  build_with_java8:
+    <<: *base_job8
 
     steps:
       - checkout
@@ -99,8 +109,32 @@
 
       - run: ./gradlew testClasses
 
+  build_with_java11:
+    <<: *base_job11
+
+    steps:
+      - checkout
+      - run: sudo apt-get update -qq
+      - run: sudo apt-get install -y libjna-java python-dev python3-pip libyaml-dev nodejs
+      - run: sudo pip3 install pyYaml ccm
+
+      - run:
+          name: Download CCM for Cache
+          command: |
+            sudo apt-get update -qq
+            sudo apt-get install -y libjna-java python-dev python3-pip libyaml-dev nodejs
+            sudo pip3 install pyYaml ccm
+            ccm create cassandra_40 --no-switch -v 4.0.6
+
+      - save_cache:
+          key: ccm
+          paths:
+            - ~/.ccm/repository
+
+      - run: ./gradlew testClasses
+
   cassandra_30:
-    <<: *base_job
+    <<: *base_job8
 
     steps:
       - checkout
@@ -108,15 +142,23 @@
           version: 3.0.17
 
   cassandra_311:
-    <<: *base_job
+    <<: *base_job8
 
     steps:
       - checkout
       - install_ccm:
           version: 3.11.4
 
+  cassandra_40:
+    <<: *base_job8
+
+    steps:
+      - checkout
+      - install_ccm:
+          version: 4.0.6
+
   build_packages:
-    <<: *base_job
+    <<: *base_job8
 
     steps:
       - checkout
@@ -125,16 +167,21 @@
 workflows:
   version: 2.1
 
-  cassandra_30:
+  cassandra_30_java8:
     jobs:
-      - build
+      - build_with_java8
       - cassandra_30
 
-  cassandra_311:
+  cassandra_311_java8:
     jobs:
-      - build
+      - build_with_java8
       - cassandra_311
 
+  cassandra_40:
+    jobs:
+      - build_with_java11
+      - cassandra_40
+
   build_everything:
     jobs:
       - build_packages
\ No newline at end of file