Determine if a Preference Node exists in Java

In order to determine the existence a preference node in Java, we use the nodeExists() method. The nodeExists() method returns a boolean value. It returns true when the specified preference node exists in the same tree as this node.

Declaration − The java.util.prefs.Preferences.remove() method is declared as follows −

public abstract boolean nodeExists(String pathname)throws BackingStoreException

where pathname is the path name of the node whose existence needs to be determined.

Let us see a program to determine if a preference node exists in Java −

Example

 Live Demo

import java.util.prefs.Preferences; public class Example {    public static void main(String[] args) throws Exception {       boolean exist = Preferences.userRoot().nodeExists("/node");       System.out.println("Checking node existence before creation: "+exist);       Preferences.userRoot().node("/node");       exist = Preferences.userRoot().nodeExists("/node");       System.out.println("Checking node existence after creation: "+exist);    } }

Output

Checking node existence before creation: false Checking node existence after creation: true Dec 26, 2018 7:12:10 AM java.util.prefs.FileSystemPreferences$1 run INFO: Created user preferences directory.