java.lang.NullPointerException的处理

1、错误程序

2、正确程序

3、分析原因：

4、正常运行测试：

package ch1.incremental;

import java.util.ArrayList;

import java.util.List;

public class MergeTest {

public static void main(String args[]) {

Integer a[] = { 1, 2, 5, 8, 9, 0, 3, 4, 6, 7 }, i;

String b[] = { "AoMen", "BeiJing", "ShangHai", "ChongQing", "TianJin",

"XiangGang" };

Double c[] = { 0.5, 3.7, 6.3, 8.5, 9.2, 1.7, 2.3, 4.1, 5.9, 7.4 };

ArrayList<Integer> A=new ArrayList<Integer>();

for(i=0;i<10;i++){

A.add(a[i]);  

}

LinearList.merge((List)A , 0, 4, 9);

System.out.println(A);

// LinearList.merge(a, 0, 4, 9);

// for (i = 0; i < 10; i++)

// System.out.print(a[i] + " ");

// System.out.println();

// LinearList.merge(b, 0, 2, 5);

// for (i = 0; i < 6; i++)

// System.out.print(b[i] + " ");

// System.out.println();

// LinearList.merge(c, 0, 4, 9);

// for (i = 0; i < 10; i++)

// System.out.print(c[i] + " ");

// System.out.println();

}

}