Topic 8.2: Handling Exceptions - Create a try-catch block and determine how exceptions alter normal program flow Flashcards
This exception is a subclass of IOException and is specifically thrown when a file is requested but cannot be found during an I/O operation.
How is the FileNotFoundException different from the IOException in Java?
What is the importance of providing meaningful error messages when throwing exceptions?
Providing descriptive and meaningful error messages helps developers diagnose and fix issues quickly by understanding what went wrong.
When is the throw keyword typically used?
This keyword is typically used within methods to raise an exception when a specific condition is met or when an error occurs that the method cannot handle itself.
These blocks in Java allow you to handle multiple exceptions in a single catch block by specifying the exception types separated by vertical bars (|) in the catch parameter.
This feature was introduced in Java SE 7 and helps reduce code duplication and improves code readability when you want to handle multiple exception types in a similar way.
How do multi-catch blocks in Java allow you to handle multiple exceptions in a single catch block?
This class is the superclass of all errors in Java.
Errors represent severe issues that may not be recoverable by application code. Examples include StackOverflowError and OutOfMemoryError.
What is the purpose of the java.lang.Error class in the exception hierarchy?
This exception occurs in Java when a method that converts a string to a numeric type encounters an inappropriate format in the input string.
When does the NumberFormatException exception occur in Java?
What should be considered when using multiple catch blocks effectively?
Order catch blocks from specific to general to ensure proper handling of exceptions.
What is the purpose of using multiple catch blocks in Java exception handling?
These allow handling various exceptions differently for improved application robustness.
This exception is thrown in Java when an arithmetic operation produces an exceptional condition, such as division by zero.
What does the ArithmeticException exception indicate, and when is it thrown in Java?
What is the purpose of the java.lang.Error class in the exception hierarchy?
This class is the superclass of all errors in Java.
Errors represent severe issues that may not be recoverable by application code. Examples include StackOverflowError and OutOfMemoryError.
When this occurs, the program’s flow of control jumps to the nearest enclosing try-catch block or terminates if there is no appropriate handler.
How does an exception alter the flow of control in a program?
These allow developers to define application-specific exceptional conditions and provide more meaningful information to the calling code about the error that occurred.
They enhance the clarity and understanding of exceptional situations and enable developers to handle errors in a more specific and context-aware manner.
Why are custom exceptions useful?
Give an example of handling a checked exception
Example:
public void handleFile() {
try {
readFile();
} catch (IOException e) {
// Handle the exception here
}
}
What does the NullPointerException exception indicate, and when is it thrown in Java?
This exception is thrown in Java when a program attempts to access a member (a field or method) of an object that is currently null.
This occurs when an object reference is pointing to nothing (null) and an operation is performed on it.
What happens if there is no matching catch block for an exception in the try block?
If there is no matching catch block, the control jumps to the nearest finally block (if present) before propagating the exception.
These allow handling various exceptions differently for improved application robustness.
What is the purpose of using multiple catch blocks in Java exception handling?
What is the syntax of the try-catch block in Java?
Basic Syntax:
try {
// Code that may throw an exception
} catch (ExceptionType1 e1) {
// Exception handling code for ExceptionType1
} catch (ExceptionType2 e2) {
// Exception handling code for ExceptionType2
}
// More catch blocks as needed
How do multi-catch blocks in Java allow you to handle multiple exceptions in a single catch block?
These blocks in Java allow you to handle multiple exceptions in a single catch block by specifying the exception types separated by vertical bars (|) in the catch parameter.
This feature was introduced in Java SE 7 and helps reduce code duplication and improves code readability when you want to handle multiple exception types in a similar way.
what is a similarity between Checked and Unchecked Exceptions
Both types of exceptions will propagate up the call stack, searching for an appropriate catch block.
If no catch block is found, both checked and unchecked exceptions will result in program termination.
These in Java are abnormal conditions or errors that disrupt the normal flow of the program when something unexpected happens during execution.
What is the role of exceptions in a Java program?
How are exceptions handled using try-catch blocks?
The code that may throw an exception is placed within the try block.
If an exception occurs, it is caught and handled by the corresponding catch block, ensuring controlled handling of exceptional situations.
What happens if you create a new exception object but do not use the ‘throw’ keyword to throw it?
If you create a new exception object without using ‘throw,’ the exception will not be propagated or caught, having no effect on the program’s flow of execution.
This is thrown when an attempt is made to cast an object to a type that is not compatible with the object’s actual type.
What is the purpose of the ClassCastException in Java?
What caution should be exercised when catching exceptions in a program?
Avoid swallowing exceptions without taking any action, as this can hide important issues and make it difficult to identify problems in the code.
In what order are catch blocks evaluated and executed when an exception is thrown?
Catch blocks are evaluated in order of appearance, and only the first matching catch block is executed.
This keyword is typically used within methods to raise an exception when a specific condition is met or when an error occurs that the method cannot handle itself.
When is the throw keyword typically used?
How does a catch block determine which exception to handle?
When an exception is thrown within the try block, the Java runtime searches for a matching catch block that can handle the specific type of exception. It checks each catch block in order of appearance to find the first one whose exception type matches the thrown exception’s type.
The exception type is determined by the class of the thrown exception or one of its subclasses.
In catch blocks, you write code that defines how to handle the caught exception gracefully. This may include:
- displaying an error message
- logging the exception
- attempting to recover from the exceptional situation
- or taking appropriate corrective actions.
The purpose of catch blocks is to handle exceptions properly to ensure the program doesn’t crash unexpectedly and provides useful information to the user or developer when an exceptional condition occurs.
What is the purpose of catch blocks in exception handling?
Is the ‘throw’ keyword required to propagate an exception to a catch block in Java?
Yes, the ‘throw’ keyword is necessary to explicitly throw an exception, causing it to propagate up the call stack to find a suitable catch block.
How is the FileNotFoundException different from the IOException in Java?
This exception is a subclass of IOException and is specifically thrown when a file is requested but cannot be found during an I/O operation.
What happens if an exception is not caught and handled in Java?
If this is not caught and handled, it propagates up the call stack, and if there is no appropriate catch block, the program terminates abruptly, displaying the exception’s details as a “stack trace.”
