[java] Updating property value in properties file without deleting other values

Content of First.properties:

name=elango
country=india
phone=12345

I want change country from india to america. This is my code:

import java.io.*;
public class UpdateProperty 
{
    public static void main(String args[]) throws Exception 
    {   
        FileOutputStream out = new FileOutputStream("First.properties");
        FileInputStream in = new FileInputStream("First.properties");
        Properties props = new Properties();
        props.load(in);
        in.close();
        props.setProperty("country", "america");
        props.store(out, null);
        out.close();
    } 
}

Output content of First.properties:

country=america

The other properties are deleted. I want update a particular property value, without deleting the other properties.

You can use Apache Commons Configuration library. The best part of this is, it won't even mess up the properties file and keeps it intact (even comments).

Javadoc

PropertiesConfiguration conf = new PropertiesConfiguration("propFile.properties");
conf.setProperty("key", "value");
conf.save();    

Properties prop = new Properties();
prop.load(...); // FileInputStream 
prop.setProperty("key", "value");
prop.store(...); // FileOutputStream