Create files without having a project.
Scratches can be found in "YourHomeDirectory/.netbeans/scratches"
Any specific reason Java 8 is required?
In some corporate environments 7 is still the only option.
"Save All" should be disabled before first "Save As..."
If I create a new file in memory and edit its content, I can "File > Save All" even though nothing is actually saved.
Unfortunately it is not possible to have 2 different functionalities for the normal save logic. So that means, that you have to add a shortcut to "Save As" (for me Ctrl + Alt + S; Ctrl + Alt + S) and then you can save the file whereever you want and change the name and extension.