IPreferencesService service = Platform.getPreferencesService();

 File exportFile = File.createTempFile(USER_PREFERENCE_FILE_PREFIX,
           USER_PREFERENCE_FILE_SUFFIX, toFolder);

 os = new FileOutputStream(exportFile);

 service.exportPreferences(service.getRootNode(), os, null);

       IPreferencesService service = Platform.getPreferencesService();
        IExportedPreferences prefs;

        try {
            prefs = service.readPreferences(new FileInputStream(new File(
                    selectedFile)));

            service.applyPreferences(prefs, getTransfers());
        } catch (FileNotFoundException e) {
            ExceptionDialog.show(e, shell);
        } catch (CoreException e) {
            ExceptionDialog.show(e, shell);
        }

        return null;
    }

    private static IPreferenceFilter[] getTransfers() {
        IPreferenceFilter[] transfers = new IPreferenceFilter[1];

        // For export all create a preference filter that can export
        // all nodes of the Instance and Configuration scopes
        transfers[0] = new IPreferenceFilter() {

            @Override
            public String[] getScopes() {
                return new String[] { InstanceScope.SCOPE,
                        ConfigurationScope.SCOPE };
            }

            @Override
            @SuppressWarnings("rawtypes")
            public Map getMapping(String scope) {
                return null;
            }
        };

        return transfers;
    }