I have Eclipse installed with WindowsBuilder, and it has worked fine in the past in showing the design tab of JFrame.
I just installed Intellj, and installed a JDK in addition to my current SE-9 JVM. My eclipse program is still functional , but is showing the following when I open WindowsBuilder design:
Incompatible Java versions: Eclipse is running under 0, but this Java project has a
9 Java compliance level, so WindowBuilder will not be able to load classes from this
project. Use a lower level of Java for the project, or run Eclipse
using a newer Java version
There must be something to the zero, rather than 1.8 or 9.
Other StackExchange answers suggest that I downgrade my Java version, but when I went to project/properties/java compiler, it did not work.
My java compiler is linked to SE-9, so I am unsure why this new error is occurring. Maybe it is due to installing the JDK as well?