The following Class create a .properties file.

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

public class WritePropertyFile {
  public static void main(String[] args) {
    Properties prop = new Properties();

    try {
      // Write the properties value
      prop.setProperty("name", "Eureka");
      prop.setProperty("url", "https://ykyuen.wordpress.com");
			
      // Save the changes
      prop.store(new FileOutputStream("src/main/resources/config.properties"), null);
    } catch (IOException ex) {
      ex.printStackTrace();
    }
  }
}

This is the output config.properties

#Sat Aug 27 23:02:57 CST 2011
url=http\://ykyuen.wordpress.com
name=Eureka

Done =)

Next Post: Java – Read .properties

Reference: Mkyong.com – Java Properties file examples