编辑AWS-SNS SDK for Unity的java类文件

I am using AWS-SNS SDK for Unity to receive notification in Android Device. After I import asset package to Unity Editor, I can setup everything and receive notification. However there is no title of notification. I should change source of sdk. I want to edit 'Utils.java' inside 'aws-unity-sns-gcm-helper.jar' file. But it is very hard to change class file inside jar file. Futhermore, there are java files before jar-generated inside sdk(AWSUnityGCMWrapper.java, GCMBroadcastReceiver.java, GCMIntentService.java, Utils.java). Is there any way to use java files instead of jar file? Where can I set up for that? Thanks.I am using AWS-SNS SDK for Unity to receive not