What I know is: the compiler writes a default no-argument constructor in the byte code. But if we write it ourselves, that constructor is called automatically. Is this phenomenon constructor overriding?
What you describe isn't overriding. If you don't specify a default constructor, the compiler will create a default constructor. If it's a subclass, it will call the default parent constructor(super()), it will also initialize all instance variables to a default value determined by the type's default value(0 for numeric types, false for booleans, or null for objects).
Overriding happens when a subclass has the same name, number/type of parameters, and the same return type as an instance method of the superclass. In this case, the subclass will override the superclass's method. Information on overriding here.