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Determining If a Preference Node Exists


In this section we are going to determine the specified Preference node exists or not.

A preference node can be created automatically by using the methods Preferences.node(), Preferences.userNodeForPackage(), or Preferences.systemNodeForPackage(). To avoid creating a node, you should first check to see if the node 'Roseindia' exists by using the method nodeExists(). If not then create the node using the method userRoot().node("/Roseindia"). In order to show the existed node we have used the method exportSubtree() which emits the xml document representing the node and its descendents.

Here is the code of NodeExists.java





import java.util.prefs.*;
public class NodeExists{
  public static void main(String []args) throws Exception{
        boolean exists = Preferences.userRoot().nodeExists("/Roseindia"); 
        exists = Preferences.userRoot().nodeExists("/Roseindia"); 
    Preferences root = Preferences.userRoot();

Output will be displayed as:

Download Source Code:



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