转到窗口|首。然后在 Java |下安装JRE ，点击添加，点击标准虚拟机，然后点击下一步，然后点击目录，找到你安装JDK 1.8的位置。最后，确保已安装的JRE列表上的复选框已打开。

I am trying to update my eclipse environment to java 8. I installed the jdk and jre version 8. I also did this:

https://wiki.eclipse.org/JDT/Eclipse_Java_8_Support_For_Kepler

then in project -> properties -> java build path -> JRE system libraries -> edit -> execution environment -> JavaSE-1.8(unbound) which is the only option that has java 8 in its name. but when I select it it says : No JREs in workspace compatible with specified execution environment: JavaSE-1.8

Go to Window | Preferences. Then under Java | Installed JREs, click "Add", click "Standard VM", then "Next", then "Directory", and find the location where you installed JDK 1.8. Lastly, make sure the checkbox next to it, on the list of installed JREs, is switched on.