A **Java properties file** is used to store configuration data or settings for a Java project. `.properties` is a file extension for files that​ store the configurable parameters of an application.

> Recompilation is not required if modifications are made to a properties file.

If any information is changed in the properties file, the Java class does not need to be recompiled; hence, a properties file is usually used to store information that is frequently changed.

Each parameter is stored as a pair of *strings*; one string stores the name of the parameter and the other stores its value. These strings are similar​ to *key-value* pairs.

# Example

Suppose that there is a Java class that takes the *username* and *password* of a user *along*​ with the *IP address* of the server that the user wants to connect to. The properties file for this class will store the three parameters as:

```
username=Hassan
password=Educative_1331
ip_address=192.168.1.3
```

The program can now ​read these parameter values from this properties file.

Java properties file

A Java properties file stores configuration data as key-value pairs, allowing updates without recompilation.