CircleCI build - fix after recent changes on CircleCI side

Builds fail, e.g. https://circleci.com/gh/scoverage/scoverage-maven-plugin/82

Check this thread https://discuss.circleci.com/t/circleci-was-unable-to-run-the-job-runner/31894/18

Configuration fixed and simplified based on example project:
https://github.com/CircleCI-Public/circleci-demo-java-spring/tree/maven

Author: gslowikowski

.circleci/config.yml

@@ -1,51 +1,16 @@
-# This configuration was automatically generated from a CircleCI 1.0 config.
-# It should include any build commands you had along with commands that CircleCI
-# inferred from your project structure. We strongly recommend you read all the
-# comments in this file to understand the structure of CircleCI 2.0, as the idiom
-# for configuration has changed substantially in 2.0 to allow arbitrary jobs rather
-# than the prescribed lifecycle of 1.0. In general, we recommend using this generated
-# configuration as a reference rather than using it in production, though in most
-# cases it should duplicate the execution of your original 1.0 config.
 version: 2
 jobs:
   build:
     working_directory: ~/scoverage/scoverage-maven-plugin
-    parallelism: 1
-    shell: /bin/bash --login
-    # CircleCI 2.0 does not support environment variables that refer to each other the same way as 1.0 did.
-    # If any of these refer to each other, rewrite them so that they don't or see https://circleci.com/docs/2.0/env-vars/#interpolating-environment-variables-to-set-other-environment-variables .
+
     environment:
-      CIRCLE_ARTIFACTS: /tmp/circleci-artifacts
-      CIRCLE_TEST_REPORTS: /tmp/circleci-test-results
       _JAVA_OPTIONS: -Xms512m -Xmx1024m
-    # In CircleCI 1.0 we used a pre-configured image with a large number of languages and other packages.
-    # In CircleCI 2.0 you can now specify your own image, or use one of our pre-configured images.
-    # The following configuration line tells CircleCI to use the specified docker image as the runtime environment for you job.
-    # We have selected a pre-built image that mirrors the build environment we use on
-    # the 1.0 platform, but we recommend you choose an image more tailored to the needs
-    # of each job. For more information on choosing an image (or alternatively using a
-    # VM instead of a container) see https://circleci.com/docs/2.0/executor-types/
-    # To see the list of pre-built images that CircleCI provides for most common languages see
-    # https://circleci.com/docs/2.0/circleci-images/
+
     docker:
-    - image: circleci/build-image:ubuntu-14.04-XXL-upstart-1189-5614f37
-      command: /sbin/init
+    - image: circleci/openjdk:8-jdk-stretch
+
     steps:
-    # Machine Setup
-    #   If you break your build into multiple jobs with workflows, you will probably want to do the parts of this that are relevant in each
-    # The following `checkout` command checks out your code to your working directory. In 1.0 we did this implicitly. In 2.0 you can choose where in the course of a job your code should be checked out.
     - checkout
-    # Prepare for artifact and test results  collection equivalent to how it was done on 1.0.
-    # In many cases you can simplify this from what is generated here.
-    # 'See docs on artifact collection here https://circleci.com/docs/2.0/artifacts/'
-    - run: mkdir -p $CIRCLE_ARTIFACTS $CIRCLE_TEST_REPORTS
-    # This is based on your 1.0 configuration file or project settings
-    - run:
-        working_directory: ~/scoverage/scoverage-maven-plugin
-        command: sudo update-alternatives --set java /usr/lib/jvm/jdk1.8.0/bin/java; sudo update-alternatives --set javac /usr/lib/jvm/jdk1.8.0/bin/javac; echo -e "export JAVA_HOME=/usr/lib/jvm/jdk1.8.0" >> $BASH_ENV
-    # Dependencies
-    #   This would typically go in either a build or a build-and-test job when using workflows
-    # Restore the dependency cache
     - restore_cache:
         keys:
         # This branch if available
@@ -54,26 +19,10 @@ jobs:
         - v1-dep-master-
         # Any branch if there are none on the default branch - this should be unnecessary if you have your default branch configured correctly
         - v1-dep-
-    # This is based on your 1.0 configuration file or project settings
     - run: java -XX:+PrintFlagsFinal -version
     - run: mvn --version
     - run: mvn verify --update-snapshots --settings .travis.settings.xml -e
-    # Save dependency cache
     - save_cache:
         key: v1-dep-{{ .Branch }}-{{ epoch }}
         paths:
         - ~/.m2
-    # Test
-    #   This would typically be a build job when using workflows, possibly combined with build
-    # This is based on your 1.0 configuration file or project settings
-    # - run: mvn verify --settings .travis.settings.xml -e
-    # Teardown
-    #   If you break your build into multiple jobs with workflows, you will probably want to do the parts of this that are relevant in each
-    # Save test results
-    # - store_test_results:
-    #     path: /tmp/circleci-test-results
-    # Save artifacts
-    # - store_artifacts:
-    #     path: /tmp/circleci-artifacts
-    # - store_artifacts:
-    #     path: /tmp/circleci-test-results