I was just wondering if someone could explain the difference of these
this is a good tutorial on the java primitive data types
http://java.sun.com/docs/books/tutorial/java/nutsandbolts/datatypes.html
also
http://en.wikipedia.org/wiki/IEEE_754#Single-precision_32_bit
in practice you analyse the data you are using in the application and select the most appropriate data types. for example if the data inputted is accurate to 3 or 4 siginficant figures use a float (typical precision 6 or 7 significant figures) - no need for the greater precision of double and calculations in double take longer than float