Exception Handling - Beginning Java 8 Fundamentals - page 348

The compiler is very particular about checked exceptions being handled by programmers. If the code in a try
block cannot throw a checked exception and its associated catch blocks catch checked exceptions, the compiler
will generate an error. Consider the following code, which uses a try-catch block. The catch block specifies an
IOException , which is a checked exception. However, the corresponding try block does not throw an IOException .
// CatchNonExistentException.java
package com.jdojo.exception;
import java.io.IOException;
// Will not compile
public class CatchNonExistentException {
public static void main(String[] args) {
int x = 10, y = 0, z = 0;
try {
z = x / y;
}
catch(IOException e) {
// Handle exception
}
}
}
When you compile the code for the CatchNonExistentException class, you would get the following compiler error:
Error(12): exception java.io.IOException is never thrown in body of corresponding try statement
The error message is self-explanatory. It states that IOException is never thrown in the try block. Therefore, the
catch block must not catch it.
One way to fix the above compiler error is to remove the try-catch block altogether. The following is another
interesting way (but not a good way) to mention a generic catch block:
// CatchNonExistentException2.java
package com.jdojo.exception;
// Will compile fine
public class CatchNonExistentException2 {
public static void main(String[] args) {
int x = 10, y = 0, z = 0;
try {
z = x / y;
}
catch(Exception e) {
// Handle the exception
}
}
}