"0x" is a prefix for hexadecimal numbers in Java. In Java, if an integer value starts with 0x or 0X, it means it is a hexadecimal number.
For example, the following code fragment assigns the integer 10 to the variable x:
int x = 0xA;
In this example, 0xA is a hexadecimal number whose decimal value is 10. Therefore, the value of x will be 10.
The integer types supported in Java include byte, short, int, long and other types. These types can be initialized and manipulated with hexadecimal values.