Mastering Exception Handling in Java

What is the purpose of a try-catch block in Java?

• To improve code readability.

• To optimize performance of the program.

• To define variables in a method.

• To handle exceptions and prevent program crashes.

How do you throw an exception in Java?

• Use 'throw new Error("message");' instead of Exception.

• Throw an exception using 'throw Exception();' with no message.

• Use 'throw new Exception("message");' to throw an exception in Java.

• Use 'throw Exception("message");' without 'new'.

What is the difference between checked and unchecked exceptions?

• Checked exceptions are always runtime errors.

• Checked exceptions require handling, while unchecked exceptions do not.

• Both checked and unchecked exceptions require handling.

• Unchecked exceptions must be declared in the method signature.

When is the finally block executed in Java?

• The finally block is executed after the try and catch blocks, regardless of exceptions.

• The finally block is executed before the try block.

• The finally block is executed only if an exception occurs.

• The finally block is executed only if there is no catch block.

Can you nest try-catch blocks in Java?

• No, try-catch blocks cannot be nested in Java.

• Yes, you can nest try-catch blocks in Java.

• You can only have one try block in Java.

• Catch blocks must always follow a try block directly without nesting.

What happens if an exception is not caught?

• The program will run faster.

• The program may terminate unexpectedly.

• The exception will be logged automatically.

• The program will continue to run without issues.

What is the syntax for a try-catch block?

• try { /* code */ } catch { /* handle error */ }

• try { /* code */ } catch (ExceptionType e) { /* handle exception */ }

• try { /* code */ } finally { /* cleanup */ }

• try (/* code */) { /* handle exception */ }

How do you create a custom exception in Java?

• public class MyCustomException extends Exception { public MyCustomException(String message) { super(message); } public MyCustomException(String message, Throwable cause) { super(message, cause); }}

• public class MyCustomException extends RuntimeException { }

• public class MyCustomException { public MyCustomException() { } }

• public class MyCustomException implements Exception { }

What is the role of the throw keyword?

• The throw keyword is used to define a function.

• The throw keyword is used to raise an exception.

• The throw keyword is used to catch exceptions.

• The throw keyword is used to declare variables.

What are some common checked exceptions in Java?

• NullPointerException

• ArrayIndexOutOfBoundsException

• IllegalArgumentException

• IOException, SQLException, ClassNotFoundException