The support for unsigned arithmetic was added to Java starting with version 8. The Byte, Short, Integer, and Long classes were affected the most by this addition.

In Java, strings representing positive numbers can be parsed as unsigned int and long types via the parseUnsignedInt() and parseUnsignedLong() JDK 8 methods. For example, let's consider the following integer as a string:

String nri = "255500";

The solution to parsing it into an unsigned int value in the radix of 36 (the maximum accepted radix) looks as follows:

int result = Integer.parseUnsignedInt(nri, Character.MAX_RADIX);

The first argument is the number, while the second is the radix. The radix should be in the range [2, 36] or [Character.MIN_RADIX, Character.MAX_RADIX].

Using a radix of 10 can be easily accomplished as follows (this method applies a radix of 10 by default):

int result = Integer.parseUnsignedInt(nri);

Starting with JDK 9, parseUnsignedInt() has a new flavor. Besides the string and the radix, this method accepts a range of the [beginIndex, endIndex] type. This time, the parsing is accomplished in this range. For example, specifying the range [1, 3] can be done as follows:

int result = Integer.parseUnsignedInt(nri, 1, 4, Character.MAX_RADIX);

The parseUnsignedInt() method can parse strings that represent numbers greater than Integer.MAX_VALUE (trying to accomplish this via Integer.parseInt() will throw a java.lang.NumberFormatException exception):

// Integer.MAX_VALUE + 1 = 2147483647 + 1 = 2147483648
int maxValuePlus1 = Integer.parseUnsignedInt("2147483648");