public String toString()
//Returns a string representation of the object
Expression Creates and calls a "new" Expression method using the specified value of the specified object.
Only constants and methods can be defined.
interface AAA {
int A1 = 1;
int A2 = 2;
void BBB();
}
Use ʻimplements` to implement an interface in a class.
class abc implements AAA{
}
Dynamically determine the type of an object. An object ・ Is it an instance of a certain class? -Is it an instance of a child class of a certain class? Is it an instance that implements a specific interface?