1Z0-829 Handling Exceptions Practice Test 3 — 15 Questions

Question 1

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 2

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 3

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 4

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

Answer

IllegalArgumentException

Question 5

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 6

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 7

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.. Option B is correct because in try-with-resources, if the try block throws an exception and the automatic close() call also throws, the close exception is added to the original exception's suppressed exceptions list (retrievable via Throwable.getSuppressed()), so the try-block exception propagates as primary. Option D is correct because the resource declaration in try-with-resources requires the type to implement java.lang.AutoCloseable (which includes Closeable), since the compiler inserts a call to close() on each resource. Option A is wrong because resources are closed in the reverse order of their declaration, not the same order. Option C is wrong because multiple resources can be declared in one try-with-resources statement, separated by semicolons. Option E is wrong because resources are closed before any catch or finally block executes, as part of the implicit finally generated by the compiler.

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 8

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.. Option D is correct because a well-designed custom exception should offer a constructor accepting a String message and a Throwable cause, allowing callers to preserve the original exception's stack trace and context via initCause/super. Option E is correct because Throwable's constructor Throwable(Throwable cause) sets the cause field directly, so calling super(cause) in a custom exception constructor automatically initializes the cause without needing an explicit initCause call. Option A is wrong because custom exceptions typically extend Exception (or RuntimeException) for application-level errors, not Error, which is reserved for serious JVM-level problems. Option B is wrong because there is no requirement or general best practice to declare custom exception classes final; subclassing is often allowed and useful. Option C is wrong because Exception is a class, not an interface, so custom exceptions extend it rather than implement it.

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 9

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

Accepted Answer

Multi-catch syntax uses the pipe symbol (|) between exception types.. Option C is correct because Java's multi-catch syntax joins exception types with the pipe symbol, as in catch (IOException | SQLException e), allowing one handler to process several unrelated exception types. Option D is correct because checked exceptions (subclasses of Exception other than RuntimeException and its subclasses) must either be caught with a try/catch or declared in the method's throws clause, otherwise compilation fails. Option E is correct because the finally block is not guaranteed to run if the JVM terminates before reaching it, for example via System.exit() or an abnormal JVM shutdown, since the finally block only executes as part of normal control flow. Option A is not correct because the catch parameter is implicitly final in both single-catch and multi-catch forms, not only in multi-catch syntax. Option B is not correct because try-with-resources does not require a finally block; resources declared in the try-with-resources header are automatically closed, and catch or finally blocks are optional.

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 10

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 11

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 12

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 13

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.

Answer

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

Answer

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

Question 14

Which of the following is a best practice when designing custom exception classes?

Accepted Answer

Extend an existing exception class and provide constructors that call the superclass constructor.. The Java best practice for custom exceptions is to extend an existing exception class (e.g., Exception or RuntimeException) and provide constructors that call the superclass constructor. This ensures the custom exception inherits the standard exception mechanism, including proper chaining, stack trace handling, and compatibility with try-catch blocks, without reinventing the wheel.

Answer

Define a custom exception with a single constructor that takes an int error code.

Answer

Extend the Throwable class directly to create a new exception type.

Answer

Use a generic Exception class with a string message to indicate the type of error.

Question 15

Consider try-with-resources where resource1 is opened first, then resource2. During closing, both throw exceptions. Which exception is propagated to the caller?

Accepted Answer

The exception from resource2 (closed first) with resource1's exception as suppressed.. In try-with-resources, resources are closed in the reverse order of their declaration. Resource2 (declared second) is closed first, and resource1 (declared first) is closed last. If both throw exceptions during closing, the exception from the first resource closed (resource2) is propagated to the caller, and the exception from the second resource closed (resource1) is added as a suppressed exception. This matches option B.

Answer

The exception from resource1 (closed last) with resource2's exception as suppressed.

Answer

Only the exception from the resource declared first is propagated.

Answer

Both exceptions are wrapped in a new exception.