Intellij IDEA stopped seeing JAVA, how to fix it?

Question

Java

For some reason, the style was reset in Intellij (the font and buttons are somehow larger and not beautiful) and, most importantly, Intellij now does not see Java. In the settings (File->ProjectStructure), of course, the version and directory that is set to JAVA_HOME is selected. The required version is also set in the compilation settings. This happened after a few months of use, I found that JAVA_HOME had an old version of 1.8. This happened after the update.
What could it be, needs to be fixed urgently?

Answer 1

Have you looked by chance? - https://stackoverflow.com/questions/29286714/intel...

Answer 2

What means does not see Java? Writes that jdk cannot determine?
If you are talking about the absence of files in the project, reimport the project: tab maven projects on the toolbar on the right -> reimport maven projects.
About the style, it’s generally not clear what you are talking about, buttons are like buttons. File -> Settings -> Appearance everything you need is there.