參考：http://blog.csdn.net/jiangtaoking/article/details/49151763
The solution is to go to Run as → External tools configuration… → JRE where the default was set to “Separate JDK”: jdk1.6.0_31 (I had set up JDKs 6-8 in Preferences after installing). I changed this to “run in the same JRE as the workspace” and now it works.