The Range of Int in Java

Why java int type has valid value in range -2,147,483,648 to 2,147,483,647?

The primary representation of numbers in modern computers is some form of binary representation. It consists of a fixed number of bits that take the values 0 or 1. In Java, an int is specified to use a binary representation with 32 bits.

A 32 bit binary representation can have 2^32 states. (This is a mathematical fact. It can be proven from first principles.)

Consider the mathematical integers from -2^31 to +2^31:

• There are 2^31 numbers in the range 1 to 2^31 (inclusive)

• There are 2^31 numbers in the range -1 down to -(2^31) (inclusive)

• The value zero is not in either of the above ranges.

So counting the numbers from -2^31 to +2^31, we get a total of 2^31 + 2^31 + 1 values. That is 2^32 + 1 which is more values than can be represented in 2^32 states.

What you are suggesting is not mathematically possible.

Java: Equivalent of Python's range(int, int)?

Guava also provides something similar to Python's range:

Range.closed(1, 5).asSet(DiscreteDomains.integers());

You can also implement a fairly simple iterator to do the same sort of thing using Guava's AbstractIterator:

return new AbstractIterator<Integer>() {
  int next = getStart();

  @Override protected Integer computeNext() {
    if (isBeyondEnd(next)) {
      return endOfData();
    }
    Integer result = next;
    next = next + getStep();
    return result;
  }
};

How to get a range of values in Java

You can use a stream to generate the range and collect it to a list

IntStream.range(0, 10)
         .collect(Collectors.toList());

Note that the first number is inclusive and the second is exclusive. You can use the rangeClosed method to include the second argument.
http://docs.oracle.com/javase/8/docs/api/java/util/stream/IntStream.html#range-int-int-

There are other types of streams for other primitives (e.g. see DoubleStream.iterate for example).

Java int vs Integer - different ranges

No. int and Integer have exactly same range.

Your program runs infinitely because when you add 1 to Integer.MAX_VALUE you get numeric overflow and result will be Integer.MIN_VALUE. Which in turn less than Integer.MAX_VALUE.

If this is practical problem, I suggest you to use long and Long instead of int and Integer

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