Java: Long result = -1: cannot convert from int to long

Question

I\'m using eclipse java ee to perform java programming.

I had the following line of code in one of my functions:

Long result = -1;

Answer 1

-1 can be auto-boxed to an Integer.

Thus:

Integer result = -1;

works and is equivalent to:

Integer result = Integer.valueOf(-1);

However, an Integer can't be assigned to a Long, so the overall conversion in the question fails.

Long result = Integer.valueOf(-1);

won't work either.

If you do:

Long result = -1L;

it's equivalent (again because of auto-boxing) to:

Long result = Long.valueOf(-1L);

Note that the L makes it a long literal.