Difficulty:Peaceful (Lock)
I was looking at the End to see the Enderdragon's new behavior, and there were 2 things I didn't spot at the End island: 1. The Enderdragon, and the portal you throw an enderpearl through to go to the end dungeons. Therefore, you cannot get the credits in peaceful mode.
Environment
Java 1.8.0_51
Windows 10 Build 10162
same over here but also in difficulty hard i had to spawn in the dragon with the clay block creeper face but than the health bar of the dragon wont show up on the screen
i made a end portal in creative wile mi difficulty was on Hard and entered the end portal wile in creative andthe dragon didnt spawn
edit: but in a second test world i made the dragon did spawn but than the difficulty was on normal and i was also in creative