一个很神奇的问题 为什么会报 Java .lang.InstantiationError 错误呢？

public class findDupicate { public static void main(String[] args) { animal i1 = new animal(); cat i2 = new cat(); } } class cat { public int age = 1; public cat() { System.out.println("this cat init "); } public void bark(){ System.out.println("this is animal"); } } class animal { public int legNum = 1; public animal(){ System.out.println("this animal init "); } public void bark(){ System.out.println("this is animal"); } } 

输出是这样的

this animal init Exception in thread "main" java.lang.InstantiationError: cat at findDupicate.main(findDupicate.java:6) 

为什么 animal 可以实例化成功 而 cat 不行呢？

jdk 版本是 open-jdk 12