Getting and Setting Properties : Properties « Collections « Java Tutorial

1. Java Tutorial
2. Collections
3. Properties

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

public class Main {
  public static void main(String[] argv) throws Exception {
    Properties properties = new Properties();
    try {
      properties.load(new FileInputStream("filename.properties"));
    } catch (IOException e) {
    }
    String string = properties.getProperty("a.b");
    properties.setProperty("a.b", "new value");
  }
}