OS X:ei Capitan This application requires the legacy Java SE 6 runtime which are unavailable for this version of OS X.

OS X:ei Capitan System Some applications will appear when the title is open.

Cause: OS X does not pre-install Java in the default state, so it must be installed manually

Workaround:

1.

1.1 Enter Java-version in terminal to view version

If the version is displayed, the instructions are installed.
If shown below, it means that the pair is not installed and needs to be restarted.

　No Java Runtime present, requesting install.

1.2 Please go directly to the latest version of Oracle website

Address: http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

2.

2.1 See changes in StackOverflowJVMVersion 来解决，我尝试了下并没有解决我的问题

Address:http://superuser.com/questions/926250/intellij-not-working-on-el-capitan-10-11

It is good to summarize 2 methods to solve single application, and the 1 method is better than expected.

Reference: https://oliverdowling.com.au/2014/03/28/java-se-8-on-mac-os-x/

OS X:ei Capitan This application requires the legacy Java SE 6 runtime which are unavailable for this version of OS X.