Suppose you have a list containing objects. You can export it to the excel file. 

You will require the following jars for this:

• xmlbeans-2.3.0.jar
• poi-3.9-20121203.jar
• poi-ooxml-3.9-20121203.jar
• poi-ooxml-schemas-3.9-20121203.jar
• dom4j-1.6.1.jar

If using maven add the following dependencies:

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.9</version>
</dependency>
<dependency>
	<groupId>org.apache.poi</groupId>
	<artifactId>poi-ooxml</artifactId>
	<version>3.9</version>
</dependency>

Example:

Suppose we have class User.java

package com.demo.rough;

public class User {	
	private String id;
	private String name;
	public User(){
		this.id="";
		this.name="";
	}
	public User(String id, String name) {
		this.id = id;
		this.name = name;
	}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
}

Then, our main class ExportList.java

import java.io.File;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ExportList {
	public static void main(String args[]) 
    {
        	List<User> list=new ArrayList<User>();
        	User user1=new User("1","John");
        	User user2=new User("2","Chris");
        	User user3=new User("3","Roth");
        	list.add(user1);
        	list.add(user2);
        	list.add(user3);    	
       
        	 try
             {	
        XSSFWorkbook workbook = new XSSFWorkbook(); 
              
        XSSFSheet sheet = workbook.createSheet("sheet1");// creating a blank sheet
         int rownum = 0;
         for (User user : list)
            {
            Row row = sheet.createRow(rownum++);
            createList(user, row);
                
        }                   
       
            FileOutputStream out = new FileOutputStream(new File("NewFile.xlsx")); // file name with path
            workbook.write(out);
            out.close();
           
        } 
        catch (Exception e) 
        {
            e.printStackTrace();
        }
    
}
  private static void createList(User user, Row row) // creating cells for each row
{
	    Cell cell = row.createCell(0);
	    cell.setCellValue(user.getId());
	 
	    cell = row.createCell(1);
	    cell.setCellValue(user.getName());
	 
	   
	}
}

So your List will be exported to excel format with the file name NewFile.xlsx and will contain the records which we entered in the list.