Taxspanner Interview Questions and Answers

Using Java stream, find the sum of all odd numbers in a list.

• Use the filter() method to filter out the odd numbers from the list.

• Use the mapToInt() method to convert the filtered numbers to integers.

• Use the sum() method to calculate the sum of the filtered odd numbers.

To remove duplicates from an ArrayList of strings, use a HashSet to store unique elements.

• Create a HashSet and add all elements from the ArrayList to it.

• Create a new ArrayList and add all elements from the HashSet to it.

• The new ArrayList will contain only unique elements.

HashSet and HashMap are both data structures in Java that use hashing to store and retrieve elements.

• HashSet uses HashMap internally to store its elements as keys with a dummy value.

• HashMap uses an array of linked lists called buckets to store key-value pairs.

• Both HashSet and HashMap use the hashCode() method to calculate the hash value of keys.

• HashSet uses the hash value to determine the bucket where an element should be stored.

• HashMap uses the hash value to determine the bu...read more

Checked exceptions are exceptions that must be declared in a method's signature or handled using try-catch blocks.

• Checked exceptions are checked at compile-time.

• They are typically used for exceptional conditions that can be reasonably recovered from.

• Examples of checked exceptions in Java include IOException, SQLException, and ClassNotFoundException.

There are two types of locks in Java - synchronized and ReentrantLock. Multithreading can be achieved by using these locks.

• Two types of locks in Java are synchronized and ReentrantLock

• Synchronized keyword can be used to achieve synchronization in Java

• ReentrantLock provides more flexibility and control over locking mechanisms

• Example: synchronized block - synchronized(obj) { // code }

• Example: ReentrantLock - ReentrantLock lock = new ReentrantLock(); lock.lock(); // code; lock.u...read more

Producer-consumer problem is a classic synchronization problem in multithreading.

• Use wait() and notify() methods for synchronization

• Create a shared buffer to store data between producer and consumer

• Ensure proper handling of synchronization to avoid race conditions

Singleton is a design pattern in Java where a class is restricted to have only one instance.

• Singleton pattern ensures that a class has only one instance and provides a global point of access to it.

• It is commonly used in scenarios where a single instance of a class is required to control actions throughout a system.

• Example: Database connection classes, Logger classes, Configuration classes.