JAVA throws规则_catch or throw java 规则-优快云博客

本文探讨了Java中异常类的继承与抛出规则，包括如何定义异常类、子类覆盖父类方法时异常声明的变化限制等核心概念。

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class A extends Exception {
}
class B extends A {
}
abstract class I {
	void fevent() throws A {};
	void gent() throws B {};
	void hent() {};
}
class C extends Exception {
}
class D extends B {
}
interface II {
	//void fevent() throws C;  此处开放CC 继承将报错.
}
class CC extends I implements II {  
	CC() throws A,C {
	}
}
public class Test{
	public static void main(String[] args){
		Integer t = null;
		if(t == null){
			throw new NullPointerException();
		}
		System.out.println("END");
	}
}

子类Overrider 方法不能抛出比父类更多的异常。(主要为的是Upcast)

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