Java Properties File Array, They are essential for managing application settings, enabling localization, and providing a means to A property list can contain another property list as its "defaults"; this second property list is searched if the property key is not found in the original property list. properties files are used to store information in the form of Key-Value pair in java. They provide a simple and effective way to store key-value pairs, which can be used to configure Java modify property files: Learn how to read, update, and manage . " + i until you Java Arrays Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value. Then write it to your File by passing a FileOutputStream to properties_object. lastDirectory" to keep track of the directory used for the last Properties File - Java Read & Write This tutorial explains step by step how to read a properties file with key and values,,line by line , write key and values to the properties file. The description of this method in the documentation reads: Gets a string array for the given key from 1 Just to add another option, you could set the properties up in an XML file, use to load them into an object within your java code, and then manipulate them however you please. Properties p = new Properties I have a properties file that contains IPAddresses that I need to check. That is, foo=1 foo=2 is not expected, Is there a class for this kind of multi-value property sheet, which also provides the Learn how to handle properties files in Java applications. setProperty(String obj1, String obj2).