Two Ways to Read Java Properties Files: ClassLoader vs ResourceBundle

Reading Java Properties Files: Two Approaches

This article demonstrates two standard ways to load configuration from a jdbc.properties file in a Java application.

Method 1: Using ClassLoader and Properties

The example uses a jdbc.properties file placed in the classpath root with the following content:

jdbc.driver= com.mysql.jdbc.cj,Driver
jdbc.url=jdbc:mysql://localhost:3306/music
jdbc.username=root
jdbc.password=123

The directory structure shows the properties file alongside the Java source.

In a test class testDemo, the file is loaded via the context class loader:

InputStream is = testDemo.class.getClassLoader.getResourceAsStream("jdbc.properties");
Properties pro = new Properties();
pro.load(is);
String driver = pro.getProperty("jdbc.driver");
String url = pro.getProperty("jdbc.url");
System.out.println(driver + url);

The output screenshot confirms the driver class name and JDBC URL are printed correctly.

Method 2: Using ResourceBundle

The ResourceBundle API provides a simpler alternative for properties files named without the .properties extension:

ResourceBundle rb = ResourceBundle.getBundle("jdbc"); // reads jdbc.properties
String name = rb.getString("jdbc.driver"); // retrieves value for key jdbc.driver
System.out.println(name);

The output screenshot shows the driver class name printed.

Both approaches are part of the Java standard library and require no external dependencies.