CircleCI で Java8 プロジェクトのビルドを通す

プロジェクトルートに circle.yml を配置して、使用する JDK を指定するだけです。
なお、とくに指定がない場合、Java7 でビルドされる模様。

circle.yml

machine:
  java:
    version: oraclejdk8

Java8 プロジェクトをこの指定なしでビルドしようとすると、以下のような例外が出て、mvn integration-test で Fail する。
参考まで。

[INFO] Compiling 5 source files to /home/ubuntu/winchester/target/classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] Failure executing javac, but could not parse the error:
javac: invalid target release: 1.8
Usage: javac <options> <source files>
use -help for a list of possible options

[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.503 s
[INFO] Finished at: 2016-02-06T16:52:09+00:00
[INFO] Final Memory: 31M/1963M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project winchester: Compilation failure
[ERROR] Failure executing javac, but could not parse the error:
[ERROR] javac: invalid target release: 1.8
[ERROR] Usage: javac <options> <source files>
[ERROR] use -help for a list of possible options
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:

[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException mvn integration-test returned exit code 1