Java Type Casting

Type Casting is use to convert value of one data type into another data type. The process of assigning a smaller data type into larger data type is known as widening or promotion. For example:

byte b = 10;
int i = b;

Assigning a larger data type value into a smaller data type is known as narrowing. In this type of assigning, loss of information may be possible.

int i = 10;
byte b = (byte)i

Convert string to numeric value

int i = Integer.valueOf("22").intValue();
long l = Long.valueOf("22").longValue();
double d = Double.valueOf("22.5").doubleValue();
float f = Float.valueOf("22.5").floatValue();

int i = Integer.parseInt (str);
long l = Long.parseLong (str);
parseInt() and parseLong() methods throw a NumberFormatException if the value of str does not present an integer.

Converting Number to String

string str = Integer.toString(i);
string str = Float.toString(f);
string str = Double.toString(d);
string str = Long.toString(l);