Implement a method that is passed two double type numbers, prints out their total and doesnt return anything

Write a method call for the method described above

Write a method that isnt passed anything, asks the user to input two integer numbers, adds them and returns the total.

Hint: search the online java document for class Scanner, and learn how to use the nextInt for integer input in Scanner class. For double type input, you need to use nextDouble method.

Write a method call for the method described above

What is the definition for method signature? Does the method signature include return type?

Assume a method accepts an int variable named age as formal parameter, and this method only accept age value that is between 20 (inclusive) and 30(exclusive). Write a range checking code block to prevent the method from accepting an out-of-range value for variable age, and if the range checking fails, this method should return immediately. Only write down this piece of range checking code.