Interface are more fundamental to Java than classes.

Sadly, at the beginning, many people came to Java from C/C++, and they did the thing we used to call "writing C/C++ code in Java".

I'm late to the Java party, I first did anything serious in it in 2009-10 and it was Android not "traditional" Java. So no idea about early Java's history.

The interfaces is the only thing i loved from it.

One day I will write a Java project that won't contain a single "class" keyword (it will have interface, anonymous classes, and static methods), as a piece of art.