The "double" Java data type is a 64-bit floating point type that supports all numbers, including those with decimals. To accept user input decimals in Java, you must first declare a "double" variable, after which you can scan the user-submitted data and then submit that data to the aforementioned variable. The key is to correctly declare the variable, as an improperly configured variable -- string, integer -- will cause Java to automatically truncate the decimal.
Declare the variable that will store the user value as a double:
Prompt the user to provide the value by using the "println" function:
system.out.println("Please submit your mileage:";
Scan the user value into the computer via the "scanner" function:
scanner scanned_value = new scanner(System.in);
Pass the scanned value to the previously declared variable by combining the scanner variable with the "nextDouble" function:
mileage = scanned_value.nextdouble();