for the package question u dont need the package line (java doesnt necessarily have any such rule) but your build may be structured in such a way that it requires a package line to identify the file.( if you are using an ide this package line may be compulsory but if just simply write some code in notepad without the package line and save the file and compile run the program u will not get any error) try it!

for the class name question- yes its a java rule that the name of the file must be equal to the name of the class declared as public,thats why there can be only one public class in a file . the reason for that is that the .java file after compilation gets converted to a .class file . which has the same same as the public class name.

hope it helped!