Hexadecimal integer literal (To indicate hexadecimal, prefix the literal with 0x or 0X) : Integer « Java Source And Data Type « SCJP

Counting from 0 through 15 in hex looks like this:

0 1 2 3 4 5 6 7 8 9 a b c d e f

Java will accept capital or lowercase letters for the extra digits. 
0XCAFE and 0xcafe are both legal and have the same value.

public class MainClass{
  public static void main(String[] argv){
    int intValue = 0x1c; //hex digits may be upper- or lowercase
    int intValue2 = 0x1C;
    int intValue3 = 0X1c;
    int intValue4 = 0X1C;

    int x = 0X0001;
    int y = 0x7fffffff;
    int z = 0xDead;
    System.out.println("x = " + x + " y = " + y + " z = " + z);
   
  }
}

x = 1 y = 2147483647 z = 57005

1.9.Integer
	1.9.1.	Ranges of the Integral Primitive Types
	1.9.2.	An integer literal is a value specified in the program source.
	1.9.3.	The default value for an integer primitive is zero.
	1.9.4.	Default Integral literal is decimal
	1.9.5.	Octal integer literal (To indicate octal, prefix the literal with 0 (zero))
	1.9.6.	Hexadecimal integer literal (To indicate hexadecimal, prefix the literal with 0x or 0X)
	1.9.7.	octal, decimal, and hexadecimal may be specified as long by placing a suffix of L or l after the number
	1.9.8.	out of range for short primitive
	1.9.9.	Assign a primitive variable using a literal or the result of an expression.
	1.9.10.	A literal integer is always an int, compiler automatically narrows the literal value to a byte
	1.9.11.	Add two bytes together and you'll get an int.
	1.9.12.	Integer literals are assumed to be of type int unless the letter L or l is appended.
	1.9.13.	Division by zero in integer arithmetic produces a runtime ArithmeticException.