Below is the java error message
java.io.IOException: Stream closed

Related to field in tasks was an optional field in salesforce classic but showing mandatory in salesforce lightning while defining a new task in oppurtunity object. Eventhough it was defined as an optional field in page layouts and field settings.Is there any seperate Page layout for lightning to correct this or is this a bug in lightning?

Can anyone suggest how to correct this?

I have implimented the custom component where it will have few input componenets and save button.
If user is changed or given data in input componenets and without savibg button if the user tries to navigate to other page by clickig the Back button(Custom Lightining button) i shoud show the alert telling that "unsaved items are availible in page.Please check and go".

Please let me know how to acheie this requirement in lightining components.

Below is the java error message
java.io.IOException: Stream closed

I get an "An object with the API name Trail__c does not exist" for the module Data Modeling: Create Custom Objects and Fields" even though I have followed the instructions for the "Hands-on-Challenge". Can some provide a solution?