Typecasting

In cases of specific programming, sometimes we need to change the data type to the other type. If both types are compatible or suitable, then Java will perform automatic type conversion. For example, we can always enter a value of int type to a variable declared with long type. However, if the types are not compatible, then we need to explicitly typecast to the variable to be converted. Typecasting is the casting process of data type to other data type.

Automatic Conversion in Java

By the time we enter a value into a variable that has a specific data type to the value of other types, then Java will internally perform automated conversion, with terms as follows:

• Both data types (origin and destination) are compatible
• The destination data type has a greater range of origin data type

For example, int data type always has greater range than byte type, so we do not need to perform explicit conversion from byte to int. Consider the following example code:

byte b = 2;
int c = b;

we don’t need to write as follow:

int c = (int) b;

Conversion of Not Compatible Data Type

We can also do the conversion from real numbers (floating-point) to integers. In such cases, a decimal value contained behind the comma will be discarded. For example, now we will convert the value of double to int. Consider the following code snippet:

double d = 274.5678;
int x = (int) d;   // Typecasting from double to int

Here, variable x will be worth 274 and the fractional value (0.5678) is discarded.