Exception in thread "main" java.lang.StackOverflowError
    at Animal.<init>(Animal.java:54)
    at AnimalState.<init>(AnimalState.java:13)
    at Animal.<init>(Animal.java:54)
    at AnimalState.<init>(AnimalState.java:13)
    at Animal.<init>(Animal.java:54)...

import java.time.Duration;

public class Save{

public static void main(String[] args){

    Animal cat = new Animal();

}

import java.time.Duration;

public  class Animal
{
public static  int hoursSinceLastMeal = 3;
public static  int energyPercent = 87;
public static  int age = 7;
public static  boolean isProliferating = false;
public static  boolean isFeedingNewborns = true;
public static  int weight = 3;


public int getId() {
    return hashCode();
}


public Animal() {
    new AnimalState( hoursSinceLastMeal, energyPercent, age, isProliferating, isFeedingNewborns, weight );
}

}

import java.time.Duration;
    import java.util.*;

    public class AnimalState extends Animal {

    public int hoursSinceLastMeal;
    public int energyPercent;
    public int age;
    public boolean isProliferating;
    public boolean isFeedingNewborns;
    public int weight;

    public AnimalState( int hoursSinceLastMeal, int energyPercent, int age,
    boolean isProliferating, boolean isFeedingNewborns, int weight){

    this.hoursSinceLastMeal = hoursSinceLastMeal;
    this.energyPercent = energyPercent;
    this.age = age;
    this.isProliferating = isProliferating;
    this.isFeedingNewborns = isFeedingNewborns;
    this.weight = weight;

    System.out.println(String.format("%s %s %s %s %s %s",
    hoursSinceLastMeal, energyPercent, age, isProliferating,
    isFeedingNewborns, weight));
    }
    }