Is it valid to have a JVM bytecode class without any constructor?

Question

AFAIK, in Java implicit constructors are always generated for a class without constructors [1], [2].

But in bytecode I could not find such restriction on the JVMS.

Answer 1

You've already answered the question yourself: a class without a constructor is absolutely valid according to JVMS. You cannot write such a class in pure Java, but it can be constructed using bytecode generation.

Think of interfaces: they are also classes without a constructor from JVM point of view. And they can also have static members (you can even invoke interface's main method from the command line).