Custom Exception
Development:
The new exception classes those are defined by developers
are called user Defined Exception or custom exception.
These classes must be subclass of either Throwable or any one of its subclass. It
must be thrown based on condition failure.
According to the business requirements developers must write
their own exception.
Its two steps process:
- Define public class deriving from java.lang.Exception.
- Define public no-arg and String parameter constructors with super() call.
For Example:
First Step:
NegativeNumberException.java
public class NegativeNumberException extends Exception
{
public
NegativeNumberException(){
super();
}
public
NegativeNumberException(String msg){
super(msg);
}
}
Using the above
custome Exception in Our logic
Compute.java
public class Compute
{
public
int add(int n)throws NegativeNumberException
{
if(n>0){
return
(n+10);
}
else
{
throw
new NegativeNumberException("Do Not Pass Number <=0");
}
}
}
Example.java
class Example
{
public
static void main(String[] args)
{
try{
int
n=Integer.parseInt(args[0]);
Compute
c=new Compute();
int
res=c.add(n);
System.out.println("Result::"+res);
}
catch(ArrayIndexOutOfBoundsException
aiobe){
System.out.println("Pleas
pass ONE positive Integer number");
}
catch(NumberFormatException
nfe){
System.out.println("Pleas
pass only integer number");
}
catch(NegativeNumberException
nne){
System.out.println(nne.getMessage());
}
}
}
