1. Convert jdk1.8 to jdk1.7
1. Under this directory
C:\Program Files (x86)\Common Files\Oracle\Java\javapath
Move these three exe to a backup directory.
2. Change the jdk version in the registry.
Use the shortcut key win+r and enter regedit. Change the version of jdk in the registry to 1.7
3. Verify the version again
4. Verify that if an error is reported, it is still the original jdk. Then you need to adjust the environment variables.
Second, convert jdk1.7 to jdk1.8
refer to the above to restore