int [][] array = {{1,2,3},{1,4}};
    System.out.println(array[1][2]);

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2

 at demo.Array.main(Array.java:31)

package home_work_4_17;
abstract class Employee{
	abstract double earnings();
}
class YearWorker extends Employee{
	double earnings(){
		System.out.println("按年領(lǐng)取1000");
		return 1000;
	}
}
class MonthWorker extends Employee{
	double earnings(){
		System.out.println("按月領(lǐng)取100");
		return 100;
	}
}
class WeekWorker extends Employee{
	double earnings(){
		System.out.println("按星期領(lǐng)取10");
		return 10;
	}
}
class Company{
	int n;
	//該公司的人數(shù)
	public Company(int n) {
		this.n=n;
		// TODO Auto-generated constructor stub
	}
	Employee E[]=new Employee[n];
	double cal(){
		//返回薪水綜合
		double sum=0;
		for (int j=0;j<n;j++){
			sum+=E[j].earnings();
		}
		return sum;
	}
}
public class work_2 {
	public static void main(String args[]) {
		Company c=new Company(3);
		c.E[0]=new WeekWorker();
		c.E[1]=new MonthWorker();
		c.E[2]=new YearWorker();
		System.out.println("總支出："+c.cal());
	}
}

class Company{
  int n;  //該公司的人數(shù)
   Employee E[]； 
  public Company(int n) {
    this.n=n;// TODO Auto-generated constructor stub
    E=new Employee[n];  
   }
  double cal(){    //返回薪水綜合
    double sum=0;
    for(int j=0;j<n;j++){
      sum+=E[j].earnings();
    }
    return sum;
  }
}

package test_a;
class people{
  int n;
  Student s[]=new Student[n];
  public people(int n) {
    this.n=n;// TODO Auto-generated constructor stub
  }
}
class Student{
  int number;
}
public class Cdcs {
  public static void main(String args[]) {
    people p=new people(3);
    System.out.println(p.s.length);
  }
}