Liferay Mobile Device Detection throws NoSuchMethodError

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.1.X EE
• Fix Version/s: 6.1.X EE
• Component/s: Portal Services > Mobile Device Rules
• Labels: None
• Git Pull Request: https://github.com/brianchandotcom/liferay-plugins-ee/pull/21798

Description
Liferay Mobile Device Detection throws NoSuchMethodError when used in Liferay 6.1.

Liferay Mobile Device Detection supports both Liferay 6.1 EE GA2+ and Liferay 6.2 EE GA1+
Reference: https://web.liferay.com/marketplace/-/mp/application/35419014

Steps to Reproduce

1. Setup an instance of Liferay 6.1 GA2
2. Deploy the latest version of Liferay Mobile Device Detection
   1. Current version used at the time: 3.0.1
3. Restart Liferay portal
4. Navigate to Control Panel > liferay.com > Mobile Device Rules
5. Add Rule Group
   1. Name: testRuleGroup
6. Manage rules for created Rule Group: testRuleGroup
7. Add Rule
   1. Name: testRule
   2. Type: Simple Rule
8. Navigate to Control Panel > liferay.com > Site Pages
9. Navigate to tab: Mobile Rule Groups
10. Click: Select Rule Group
    1. Choose: testRuleGroup
11. Navigate to home:
    1. http://localhost:8080/web/guest/home

Expected:
Site loads.
Actual:
HTTP 500 error is displayed in the browser and the following error is thrown in the logs:

Jun 21, 2017 7:21:00 PM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet Main Servlet threw exception
java.lang.NoSuchMethodError: com.liferay.portal.kernel.util.StringUtil.equalsIgnoreCase(Ljava/lang/String;Ljava/lang/String;)Z