我有一个抽象的类叫做动物à在它里面我有一个抽象的方法叫做乘法。如何检查这个方法是抽象的还是不使用JUnit5？

public abstract class Animal {
    private final int age;
    private final int speed;

    public Animal (int age,int speed) {
        if(age > 0) {
            this.age = age;
        }
        else {
            throw new IllegalArgumentException("Age can't be less than 0");
        }
        if(speed > 0) {
            this.speed = speed;
        }
        else {
            throw new IllegalArgumentException("Speed can't be less than 0");
        }
    }
    public static void main(String[] args) {
    }
    @Override 
    public boolean equals(Object anotherObject) {
           if (this == anotherObject) {  
                  return true;  
              }else {
                  return false;
              }
    }
    public abstract Animal[] multiply(int n);

    private boolean isFaster(Animal a) {
        if(this.getSpeed() >a.getSpeed()) {
            return true;
        }else {
        return false;
        }
    }

    private boolean isOlder(Animal a) {
        if(this.getAge() >a.getAge()) {
            return true;
        }
        return false;
    }
    @Override
    public String toString() {
        return this.getClass()+ "is " + this.getAge() + " years old, is " +this.getSpeed() +" units fast.";

    }
    public final int getAge() {
        return age;
    }

    public final int getSpeed() {
        return speed;
    }

}

我知道如何通过输入这个

Class<Animal> clazz = Animal.class;
        Assertions.assertTrue(Modifier.isAbstract(clazz.getModifiers()));

如何对抽象方法进行等价处理？