Interview Prep
Java Interview Questions 2023
What is the purpose of the transient keyword in Java?
The transient keyword is used in Java to indicate that a variable should not be serialized when an object is transformed into a byte stream. This is useful when certain variables, such as passwords or temporary data, should not be persisted.
What are the differences between throw and throws keywords in Java?
The throw keyword is used to explicitly throw an exception within a method or block, while the throws keyword is used in the method signature to indicate that the method may throw one or more specific exceptions. In other words, throw is used to raise an exception, while throws is used to declare that an exception might be thrown.
Explain the differences between ArrayList and LinkedList in Java.
ArrayList and LinkedList are both implementations of the List interface in Java, but they have significant differences. ArrayList is backed by an array and provides fast random access, making it suitable for scenarios that involve frequent element retrieval. On the other hand, LinkedList uses a doubly-linked list and offers efficient insertion and deletion operations, making it ideal for scenarios that involve frequent modification of the list.
What is the purpose of the finalize() method in Java?
The finalize() method is a part of the garbage collection mechanism in Java. It is called by the garbage collector before an object is permanently removed from memory. This method can be overridden to include any necessary cleanup code, such as releasing resources or closing connections, before the object is destroyed.
What is the difference between the equals() and == operators in Java?
The equals() method is used to compare the contents of two objects for equality, while the == operator is used to check whether two object references point to the same memory location. In simpler terms, equals() compares the values, whereas == compares the references.
Explain the concept of autoboxing and unboxing in Java.
Autoboxing and unboxing are mechanisms introduced in Java to automatically convert between primitive types and their corresponding wrapper classes (e.g., int to Integer). Autoboxing allows you to assign a primitive value to an object of the corresponding wrapper class, while unboxing allows you to extract the primitive value from the wrapper class object.
What are the differences between the final, finally, and finalize keywords in Java?
The final keyword is used to indicate that a variable, method, or class cannot be changed or overridden. The finally block is used in exception handling to specify a code block that will be executed regardless of whether an exception is thrown or not. The finalize() method, as discussed earlier, is called by the garbage collector before an object is destroyed.
Conclusion:
By familiarizing yourself with these exclusive Java interview questions and their appropriate answers, you will be better prepared to showcase your knowledge and skills during your interview as a fresher. Remember to not only memorize the answers but also understand the underlying concepts. Additionally, be prepared to elaborate on your answers and provide real-world examples when necessary. Good luck with your interview and your journey as a Java developer!