Exception handling - Java

[amit dutt]

here are 2 versions of same program:

version 1:


package dutt;

class App{

static void demo(){
try{
throw new NullPointerException("generic");
}catch(NullPointerException q){
System.out.println("caught inside demo");
throw q;
}
}

public static void main(String args[]){
try{
demo();
}catch(NullPointerException q){
System.out.println("caught inside main: " +q);
}
}
}


version 2:


package dutt;

class App{

static void demo(){
try{
throw new Exception("generic");
}catch(Exception q){
System.out.println("caught inside demo");
throw q;
}
}

public static void main(String args[]){
try{
demo();
}catch(Exception q){
System.out.println("caught inside main: " +q);
}
}
}


the only difference is I had used generic Exception class for version2 of program. while the version1 compiles without error, i get error in the version2: [Unhandlled exception type Exception]. i couldn't understand the reason. please help..

IDE used: Eclipse

 

[Prime_Coder]

U got the error in the second version of this program, because of the statement:

throw q;

This statement is out of place.

Since 2nd version uses Exception class, you need to either put that statement in next try catch block (means u write nested blocks, in this case) OR Add a "throws" statement to the demo() signature just like:

static void demo() throws Exception

This approach requires any method that calls demo() to provide exception handling for demo()