Java Exception Handling and Strings

What are the two main categories of exceptions in Java?

• Runtime exceptions and compile-time exceptions

• Synchronous exceptions and asynchronous exceptions

• Logical exceptions and physical exceptions

• Checked exceptions and unchecked exceptions

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

• To define variables in a method.

• To optimize performance of the program.

• To handle exceptions and prevent program crashes.

• To improve code readability.

How do you create a custom exception class in Java?

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

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

• public class MyCustomException implements Exception { }

• public class MyCustomException extends RuntimeException { }

Which method is used to find the length of a string in Java?

• length()

• getLength()

• size()

• stringLength()

What is the difference between checked and unchecked exceptions?

• Both checked and unchecked exceptions must be handled in the code.

• Unchecked exceptions must be declared in the method signature.

• Checked exceptions must be handled or declared; unchecked exceptions do not.

• Checked exceptions are always runtime errors.

How do you handle multiple exceptions in a single catch block?

• Only catch the most specific exception type.

• Ignore exceptions and let them propagate up the call stack.

• Use separate catch blocks for each exception type.

• Use a single catch block with multiple exception types separated by a pipe (|).

What method would you use to convert a string to lowercase in Java?

• string.lowercase()

• string.toLowerCase()

• string.toLower()

• string.convertToLower()

What is the structure of a Java package?

• A Java package is a graphical user interface component in Java.

• A Java package is a collection of Java methods only.

• A Java package is a namespace that organizes related classes and interfaces, defined by the 'package' keyword and structured in a directory hierarchy.

• A Java package is a type of variable used in Java programs.

How do you import a specific class from a package in Java?

• import packageName.ClassName();

• import ClassName as alias from packageName;

• import packageName.ClassName;

• import ClassName from packageName;

What is the purpose of the finally block in exception handling?

• To handle exceptions that occur in the try block only.

• To define a block of code that can throw exceptions.

• To replace the need for catch blocks in exception handling.

• To ensure that code runs after try and catch blocks, regardless of whether an exception occurred.