The long primitive

By default, long is a 64-bit signed integer (in Java 8, it can be either signed or unsigned). Signed, it can store a minimum value of -263, and a maximum value of 263 - 1, and unsigned it can store a minimum value of 0 and a maximum value of 264 - 1

long example = -42;
long myLong = 284;
long anotherLong = 73;

//an "L" must be appended to the end of the number, because by default,
//numbers are assumed to be the int type. Appending an "L" makes it a long
//as 549755813888 (2 ^ 39) is larger than the maximum value of an int (2^31 - 1),
//"L" must be appended 
long bigNumber = 549755813888L;

long addedLongs = myLong + anotherLong; // 284 + 73 = 357
long subtractedLongs = myLong - anotherLong; // 284 - 73 = 211

The maximum and minimum values of long can be found at:

long high = Long.MAX_VALUE;    // high == 9223372036854775807L
long low = Long.MIN_VALUE;     // low == -9223372036854775808L

The default value of a long is 0L

long defaultLong;    // defaultLong == 0L

Note: letter “L” appended at the end of long literal is case insensitive, however it is good practice to use capital as it is easier to distinct from digit one:

2L == 2l;            // true

Warning: Java caches Integer objects instances from the range -128 to 127. The reasoning is explained here: https://blogs.oracle.com/darcy/entry/boxing_and_caches_integer_valueof

The following results can be found:

Long val1 = 127L;
Long val2 = 127L;

System.out.println(val1 == val2); // true

Long val3 = 128L;
Long val4 = 128L;

System.out.println(val3 == val4); // false

To properly compare 2 Object Long values, use the following code(From Java 1.7 onward):

Long val3 = 128L;
Long val4 = 128L;

System.out.println(Objects.equal(val3, val4)); // true

Comparing a primitive long to an Object long will not result in a false negative like comparing 2 objects with == does.