Java 11 and 12 – New Features

Using var with primitive data types

Using var with primitive data types seems to be the simplest scenario, but appearances can be deceptive. Try to execute the following code:

var counter = 9_009_998_992_887;       // code doesn't compile 

You might assume that an integer literal value (9_009_998_992_887, in this case) that doesn't fit into the range of primitive int types will be inferred to be a long type. However, this doesn't happen. Since the default type of an integer literal value is int, you'll have to append the preceding value with the suffix L or l, as follows:

var counter = 9_009_998_992_887L;       // code compiles 

Similarly, for an int literal value to be inferred as a char type, you must use an explicit cast, as follows:

var aChar = (char)91; ...