1Z0-829 Handling Exceptions Practice Test 2 — 15 Questions

Question 1

Given a try-with-resources statement where both the try block and the close method of the resource throw exceptions, which of the following is true about exception handling?

Accepted Answer

The try block exception is the primary exception; the close exception is suppressed.. In a try-with-resources statement, if both the try block and the resource's close() method throw exceptions, the exception from the try block is the primary exception, and any exception thrown by close() is added as a suppressed exception. This is defined by Java's try-with-resources semantics (JLS §14.20.3.2), ensuring the primary exception is not masked by resource cleanup failures.

Answer

The exception from the close method is the primary exception.

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Both exceptions are thrown simultaneously, causing a multi-catch.

Answer

The close method exception is ignored if the try block succeeds.

Question 2

In a try-finally block, what happens to a return statement inside the finally block?

Accepted Answer

The return in the finally block is executed, and the try block return is ignored.. In a try-finally block, the finally block is always executed. If the finally block contains a return statement, that return value overrides any return value from the try block. Therefore, option A is correct. Option B is incorrect because the finally block always executes regardless of a return in try. Option C is incorrect because the finally return overrides the try return. Option D is incorrect because a return in finally is executed even if an exception occurs, overriding the exception.

Answer

The finally block is skipped if there is a return in try.

Answer

The return in the try block takes precedence.

Answer

If the try block throws an exception, the finally block's return is skipped.

Question 3

Which of the following is a best practice when creating a custom exception class?

Accepted Answer

Extend RuntimeException for an unchecked exception.. Extending RuntimeException is the standard way to create a custom unchecked exception in Java. Unchecked exceptions do not require explicit handling via try-catch or throws clauses, making them suitable for programming errors like invalid arguments or illegal states. This aligns with Java's exception hierarchy where RuntimeException and its subclasses are unchecked.

Answer

Implement the Exception interface.

Answer

Extend Error to indicate a serious system error.

Answer

Extend Throwable directly to create a new exception type.

Question 4

Given the following assertion: assert age >= 0 : "Age must be non-negative"; When is it appropriate to use assertions?

Accepted Answer

To verify internal invariants of a private method.. Assertions are used to verify internal invariants of a private method during development and testing. They should not be used for argument validation in public methods, handling recoverable conditions, or validating external input. Therefore, option A is correct.

Answer

To handle recoverable conditions like file not found.

Answer

To check parameters of a public API method.

Answer

To validate user input from an external system.

Question 5

Which of the following is a checked exception in Java?

Accepted Answer

SQLException. SQLException is a checked exception because it extends Exception directly (not RuntimeException). Checked exceptions must be either caught with a try-catch block or declared in the method signature using 'throws'. SQLException is thrown by JDBC API methods when database access errors occur, forcing the developer to handle potential SQL failures at compile time.

Answer

NullPointerException

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ArrayIndexOutOfBoundsException

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IllegalArgumentException

Question 6

Consider the following code:

public void process() throws Exception {
    try {
        riskyMethod();
    } catch (IOException | SQLException e) {
        throw e;
    }
}

Assuming riskyMethod() declares both IOException and SQLException, what is the result?

Accepted Answer

The code compiles and runs correctly.. In Java 7+, multi-catch variables are implicitly final, so they can be rethrown without a cast. The compiler knows that the thrown exception is exactly one of the caught types (IOException or SQLException), and since both are checked exceptions declared in the method signature, the code compiles and runs correctly. Option D is correct.

Answer

Compilation fails because you cannot rethrow a multi-catch variable.

Answer

Compilation fails because the catch variable must be cast to Exception.

Answer

The code compiles, but throws a ClassCastException at runtime.

Question 7

Given an exception chain where a custom exception is created with a cause, which method is used to set the cause after construction?

Accepted Answer

initCause(Throwable). `initCause(Throwable)` is the method provided by the `Throwable` class to set the cause of an exception after the exception has been constructed. This is useful when the exception must be created without a cause (e.g., via a no-arg constructor) and the cause is determined later. The cause can only be set once; a second call will throw an `IllegalStateException`.

Answer

The cause can only be set via constructor.

Answer

setCause(Throwable)

Answer

addSuppressed(Throwable)

Question 8

Which TWO statements about try-with-resources are true? (Choose two.)

Accepted Answer

If both the try block and the close method throw exceptions, the close exception is suppressed.. When both the try block and the close method throw exceptions, the exception from the close method is suppressed and added to the suppressed exceptions list of the exception thrown by the try block. This behavior is defined by the try-with-resources specification in Java, ensuring that the primary exception is not masked by resource-closing exceptions.

Answer

Resources are closed in the order they are declared.

Answer

Only a single resource can be managed in a try-with-resources statement.

Answer

Resources are closed after the catch block if an exception occurs.

Question 9

Which TWO statements about creating custom exceptions are correct? (Choose two.)

Accepted Answer

It is good practice to provide a constructor that takes a String message and a Throwable cause.. It is a well-established best practice in Java to provide a constructor that accepts both a String message and a Throwable cause, enabling precise error reporting and chaining of exceptions. This allows developers to pass a human-readable description along with the underlying cause, which is essential for debugging and logging.

Answer

Custom exceptions should extend Error to indicate fatal errors.

Answer

Custom exception classes should be declared final to prevent subclassing.

Answer

Custom exceptions must implement the Exception interface.

Question 10

Which THREE statements about exception handling are true? (Choose three.)

Accepted Answer

Multi-catch syntax uses the pipe symbol (|) between exception types.. Java's multi-catch syntax allows a single catch block to handle multiple exception types by separating them with the pipe symbol (|). This reduces code duplication when different exceptions require the same handling logic.

Answer

The variable in a catch clause is effectively final only when using multi-catch syntax.

Answer

A finally block is mandatory in a try-with-resources statement.

Question 11

Given the exhibit showing a compilation error at line 5 of Test.java, which of the following code fragments could be at that line?

Accepted Answer

FileInputStream fis = new FileInputStream("test.txt");. The code at line 5 is a checked exception (FileNotFoundException) that must be handled or declared. The compilation error indicates that the method containing line 5 does not handle or declare this checked exception, which is required by the Java compiler.

Answer

int x = 5;

Answer

try { ... } catch (Exception e) { }

Answer

System.out.println("Hello");

Question 12

Given the exhibit showing output from a program that uses try-with-resources, which of the following best describes the program?

Accepted Answer

Both the try block and the close method threw exceptions.. The output shows both a primary exception from the try block and a suppressed exception from the close method. In try-with-resources, if both the try block and the close method throw exceptions, the primary exception from the try block is propagated, and the close method's exception is added as a suppressed exception. The output displays both exceptions, confirming that both occurred.

Answer

The try block threw an exception, but the resource closed successfully.

Answer

Only the close method threw an exception, and the try block did not throw.

Answer

The close method threw an exception, and the try block completed normally.

Question 13

Given the code in the exhibit, which of the following is true about this custom exception?

Accepted Answer

It is an unchecked exception.. The custom exception extends RuntimeException, which makes it an unchecked exception. Unchecked exceptions do not require handling or declaration in the method signature, and they can be used in multi-catch blocks.

Answer

It cannot be used with multi-catch because it is unchecked.

Answer

It must be caught or declared in the method signature.

Answer

It must implement the Serializable interface.

Question 14

A developer is implementing a method that reads a file and parses its contents. The method should ensure that any resources opened during the process are properly closed, even if an exception occurs. Which approach guarantees resource closure with minimal code?

Accepted Answer

Use try-with-resources with the resource declared in the try clause.. Try-with-resources automatically closes any resource that implements `AutoCloseable` (or `Closeable`) at the end of the try block, regardless of whether an exception occurs. This guarantees resource closure with minimal code, as the developer does not need to write explicit `close()` calls or manage finally blocks.

Answer

Use a try-catch block and close the resource inside the catch block.

Answer

Use a try block followed by a finally block without catch.

Answer

Use a try-catch-finally block and call close() in the finally block.

Question 15

A method catches multiple exceptions using a multi-catch clause. Which statement about the exceptions in a multi-catch clause is correct?

Accepted Answer

The exceptions must be disjoint; if one is a subclass of another, the code will not compile.. Java requires that exception types in a multi-catch clause be disjoint (i.e., not in a subclass/superclass relationship). If one exception is a subclass of another, the code will not compile because the catch block would be unreachable for the subclass exception, violating the rule that catch blocks must be ordered from most specific to most general. This ensures that the multi-catch clause is unambiguous and that each exception type is distinct.

Answer

All exceptions in a multi-catch must be unchecked exceptions.

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The multi-catch clause can have up to three exception types.

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The exceptions can be in any order, and the first matching catch handles the exception.