Question 1

When you deserialize an object using the readObject method, you must cast the return value to the desired class type.

Accepted Answer

The readObject method returns an object of type Object, so you must cast it to the desired class type to use it as that type.

Question 2

Beginning with Java7, to catch multiple exceptions with a single catch, you can use __________.

Accepted Answer

Multi-catch allows a single catch block to handle more than one type of exception by separating the exception types with a vertical bar (|).

Question 3

A class must implement the Serializable interface in order for the objects of the class to be serialized.

Accepted Answer

Serialization in Java requires that a class implements the Serializable interface to indicate that instances of the class can be serialized by the runtime, as this interface marks the class as capable of being converted into a byte stream.

Question 4

All of the exceptions you will handle are instances of classes that extend the __________ class.

Accepted Answer

All exceptions in Java are subclasses of the `java.lang.Exception` class, which is used for exceptional conditions that a user's program should catch.

Question 5

The throw statement informs the compiler that a method throws one or more exceptions.

Accepted Answer

The throw statement is used to actually throw an exception, indicating that an error or unexpected situation has occurred. The throws keyword in method signatures is used to inform the compiler that a method might throw one or more exceptions.

Question 6

The ability to catch multiple types of exceptions with a single catch clause is known as multi-catch and was introduced in Java 7.

Accepted Answer

Multi-catch allows a single catch block to handle more than one type of exception, reducing code duplication and improving readability, and it was indeed introduced in Java 7.

Question 7

The call stack is an internal list of all the methods that are currently executing.

Accepted Answer

The call stack is a data structure that stores information about the active subroutines or methods of a computer program. It keeps track of the point to which each active subroutine should return control when it finishes executing.

Question 8

If the class SerializedClass contains references to objects of other classes as fields, those classes must also implement the Serializable interface in order to be serialized.

Accepted Answer

For an object to be serializable, all of its fields, as well as the fields of its fields (recursively), must be serializable unless marked as transient. This means if a class contains references to objects of other classes, those classes must also implement the Serializable interface for the object to be serialized properly.

Question 9

When catching multiple exceptions that are related to one another through inheritance you should handle the more general exception classes before the more specialized exception classes.

Accepted Answer

When catching multiple exceptions that are related through inheritance, you should handle the more specialized exception classes before the more general exception classes. This is because if you catch the general exception first, the specialized exceptions will never be reached.

Question 10

The throws clause causes an exception to be thrown.

Accepted Answer

The throws clause is used in a method declaration to indicate that the method may throw one or more exceptions, but it does not actually throw them.

Question 11

In a try statement, the try clause must appear first, followed by all of the catch clauses, followed by the optional finally clause.

Accepted Answer

In a try statement, the try block indeed comes first to enclose the code that might throw an exception, followed by one or more catch blocks to handle different exceptions, and finally, the optional finally block executes regardless of whether an exception was thrown or caught, making the statement accurate.

Question 12

When you write a method that throws a checked exception, you must __________.

Accepted Answer

When you write a method that throws a checked exception, it is required to declare the exception using a throws clause in the method's header. This informs the compiler and the calling methods that this method might throw an exception, and it must be handled or declared further up the call stack.

Question 13

The catch clause __________.

Accepted Answer

The catch clause indeed starts with the word "catch" followed by a parameter list in parentheses containing an ExceptionType parameter variable, follows the try clause, and contains code to gracefully handle the exception type listed in the parameter list. Therefore, it does all of these.

Question 14

When an exception is thrown by a method that is executing under several layers of method calls, a stack trace indicates the method executing when an exception occurred and all of the methods that were called in order to execute that method.

Accepted Answer

A stack trace provides a list of method calls from the point where the exception was thrown all the way back to the start of the thread, showing the method that was executing at the time of the exception and each method call that led up to it.

Question 15

When the code in a try block may throw more than one type of exception, you need to write a catch clause for each type of exception that could potentially be thrown.

Accepted Answer

In Java, when multiple types of exceptions can be thrown within a try block, it is a common practice to write separate catch clauses for each type of exception to handle them appropriately and distinctly. This allows for more specific error handling and recovery strategies for each exception type.

Question 16

When an object is serialized, it is converted into a series of bytes that contain the object's data.

Accepted Answer

Serialization is the process of converting an object into a series of bytes to store the object or transmit it to memory, a database, or a file. Its main purpose is to save the state of an object in order to be able to recreate it when needed. The reverse process is called deserialization.

Question 17

In versions of Java prior to Java 7 each catch clause could handle only one type of exception.

Accepted Answer

Before Java 7, each catch block could only handle one type of exception, requiring multiple catch blocks for different types of exceptions. Java 7 introduced multi-catch blocks, allowing a single catch block to handle multiple types of exceptions.

Question 18

When writing a string to a binary file or reading a string from a binary file, it is recommended that you use __________.

Accepted Answer

Methods that use UTF-8 encoding are recommended for writing strings to or reading strings from binary files because UTF-8 is a widely supported character encoding that can represent a vast array of characters from different languages in a binary format. This ensures that the data is stored efficiently and can be read correctly on different systems. FileReader and Writer, Scanner, and System.In/Out are not specifically designed for handling binary data and UTF-8 encoding in the context of binary files.

Question 19

All exceptions are instances of classes that extend the __________ class.

Accepted Answer

All exceptions in Java are instances of classes that extend the Throwable class, which is the superclass of all errors and exceptions in the Java language.

Question 20

A catch clause that uses a parameter variable of the Exception type is capable of catching any exception that extends the Error class.

Accepted Answer

A catch clause with a parameter of the Exception type can catch exceptions that are subclasses of Exception, but not errors which are subclasses of the Error class. Errors and Exceptions are separate subclasses of Throwable.

Quiz 11: Exceptions and Advanced File Io