RuntimeException
RuntimeExceptions do not require try/catch blocks in the code. They can usually be avoided with proper coding practices. However, when mistakes are not detected and the RuntimeException is uncaught, it will cause the application to fail and display issue information that the user may not always understand. In this exercise, you will see what happens when you don't catch a possible RuntimeException and what happens when you do try/catch them.
Deze oefening maakt deel uit van de cursus
Data Types and Exceptions in Java
Oefeninstructies
- Examine the
withoutTryCatch()andwithTryCatchmethods in this application and note the difference between them. - Run the application without changes - which results in the
withoutTryCatch()method to execute that causes aRuntimeException. - Comment out line 5 and uncomment line 7, and then rerun the application, which results in the
withTryCatch()method executing, which this time handles theRuntimeException.
Praktische interactieve oefening
Probeer deze oefening eens door deze voorbeeldcode in te vullen.
public class RuntimeExceptionHandling {
public static void main(String[] args) {
// Comment out this line
withoutTryCatch();
// Uncomment this line
// withTryCatch();
}
public static void withoutTryCatch() {
String[] mounts = { "Everest", "K2", "Kangchenjunga", "Lhotse" };
String selectedMount = mounts[4];
System.out.println("Selected item is: " + selectedMount);
}
public static void withTryCatch() {
try {
String[] mounts = { "Everest", "K2", "Kangchenjunga", "Lhotse" };
String selectedMount = mounts[4];
System.out.println("Selected item is: " + selectedMount);
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("Oops - made a mistake accessing the mounts array with a bad index.");
}
}
}