Transferring Contacts via a Google Account:

You can transfer the contacts stored on the Ace 2 to the Ace 4 by simply sync them with your Google account. Once that's done, you can then re-sync the contacts from Google with your Galaxy Ace 4, as explained below.

1. Register your Google account on the Galaxy Ace 2
2. While on the home screen, press "Menu"
3. Tap "Settings" and go to "My accounts"
4. Tap "Google" and then tap your "email address" or "user name"
5. Clear and mark the check box next to "Sync Contacts", or tap "Sync now"
6. Grab the Galaxy Ace 4 and register the same Google account as the one used on the Ace 2
7. On the Ace 4, tap "Apps" and go to "Settings"
8. Tap "Accounts" under "User and Backup"
9. Press "Menu" and then tap "Sync all"

Using the "Contacts" App to Import and Export Contacts:

The "Contacts" app that comes pre-loaded on Samsung's smartphones can be used to export the contacts from the Ace 2 in the form of a VCF file, which can then be transferred to the Ace 4 via email or using a computer, and imported via the same "Contacts" app.

1. Launch the "Contacts" app on the Galaxy Ace 2
2. Access the "Contacts" tab and press "Menu"
3. Tap "Contacts to display" > "All contacts"
4. Press "Menu" and then tap "Import / Export"
5. Tap "Export to SD card" and make sure you recall the file's name before tapping "OK"
6. Open the email client and then start a new email
7. Attach the exported VCF file to the email and send it to your own Gmail address
8. Switch over to the Galaxy Ace 4 and then open the email containing the VCF file
9. Download the vCard file and launch the "Contacts" app
10. Press "Menu" > "Import / Export" and select "Import from SD card" or "Import from storage", depending on where the VCF file has been saved
11. If necessary, select an account and browse for > select the VCF file

NOTE: As soon as you have created the VCF file on the Galaxy Ace 2, you can transfer the file to the Galaxy Ace 4 by connecting both smartphones to a computer via USB, and then manually transfer the file from the Ace 2's memory, to the Ace 4's "sdcard" directory. Finally, import the file via the "Contacts" app, as explained above

Using the "Send Anywhere" App to Share Your Contacts:

Last but not least, you can use the "Send Anywhere" application to transfer the contacts stored on your Ace 2 without needing access to a computer. Send Anywhere is a third party app that can transfer contacts and other types of files cross-platform, via a P2P connection.

1. Open the Google Play Store and install "Send Anywhere" on both of your Samsung devices
2. Once the app has been installed, launch it on both smartphones
3. On the sender device, tap "Send" > "Contacts"
4. Select the contacts that you want to share and then tap "Send"
5. Finally, you will need to select a method of transfer. Tapping "Receive" on the Ace 4 will allow you to type in the randomly generated transfer code from the Ace 2, and commence the transfer. Alternatively you can tap "Generate QR Code" on the Ace 2, and then scan the resulting code with the Ace 4's camera