what are .class files

Answer 1

It's a file containing bytecode. When you compile your .java files, they get converted into .class files.

Answer 2

when you execute java code in JVM, it create .class file. it is a class file that works same as you can import that like a normal class.

Answer 3

.class file make after compile java file

Answer 4

They are complied version of the java code you have written.