java方法 调用 问题

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

public  class Writer {

int n=0;

String bookName;

public  void addComputerB(String name)

{

++n;

bookName = name;

try {

FileWriter filew= new FileWriter(new File("计算机类.txt"));

BufferedWriter br = new BufferedWriter(filew);

br.write(bookName);

br.newLine();

br.flush();

br.close();

filew.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public String getName(String Bname)

{

return Bname;

}

public static void main(String[] args) {

// TODO Auto-generated method stub

addComputerB(getName("《核心技术》"));//为什么在此处提示有问题，说必须将方法改成静态的 啥原因呢？

System.out.println(n);

}

}