java: 怪异的代码

java:

package com.atithmetic;
public class Arithmetic {
	public Arithmetic() {
	}

	public void fengjie(int n) {
		for (int i = 2; i <= n / 2; i++) {
			if (n % i == 0) {
				System.out.print(i + "*");
				fengjie(n / i);
			}
		}
		System.out.print(n);
		System.out.println("before: System.exit(0)");
		//System.exit(0);//不能少这句，否则结果会出错
	}

	public static void main(String[] args) {
		
		Arithmetic c = new Arithmetic();
		int N = 121;
		System.out.print(N + "分解质因数：" + N + "=");
		c.fengjie(N);
		
	}
}