The data type boolean is incompatible for converting into any other data type. That is, a boolean value cannot be converted into any other data type like char, int, double etc. The maximum permitted is one boolean can be assigned to another boolean. That is, boolean to double is not possible.
Following are not permitted.
boolean b = true;
double x = b; // error, boolean to double
double x = 10.5;
boolean y = x; // error, double to boolean
boolean b = true;
char ch = b; // error, boolean to char
char ch = 'A';
boolean b =ch; // error, char to boolean
Following is permitted (boolean assignment).
boolean b = true;
boolean b1 = b; // permitted
System.out.println(b1); // prints true
The keyword boolean is used in comparison operations.
int x = 10;
int y = 20;
boolean b = (x = = y);
System.out.println(b); // prints false
Let us write a simple example to see the compiler error message when boolean to double is casted.
public class Conversions
{
public static void main(String args[])
{
boolean b1 = true;
double d1 = b1; // error
System.out.println(d1);
}
}
Error message when boolean to double casted
