Machine Learning

  How does multithreading work in Java? Multithreading is a way of achieving concurrent execution of multiple tasks in Java. Multithreading allows multiple threads to run simultaneously within a single program, enabling a program to perform several tasks concurrently. In Java, multithreading is implemented using the Thread class or the Runnable interface. Each thread represents a separate path of execution in the program and can perform different tasks concurrently. To create a new thread, you can either extend the Thread class and override the run() method, or implement the Runnable interface and pass an instance of the implementation to the Thread constructor. Common synchronization issues in multithreading that you might encounter are: Race conditions: A race condition occurs when two or more threads access a shared resource simultaneously and cause unpredictable results. This can occur when multiple threads read and write to the same variable without proper synchronization. Dea...

  Difference between a stack and a queue in Java, and when would you use each one? A stack and a queue are both data structures used to store and manipulate collections of elements in Java. However, there are some significant differences between the two: Ordering: A stack follows the LIFO (Last In First Out) order, while a queue follows the FIFO (First In First Out) order. Operations: A stack supports push and pop operations, while a queue supports enqueue and dequeue operations. Implementation: A stack can be implemented using an array or a linked list, while a queue is typically implemented using a linked list. Usage: Stacks are commonly used in programming for operations that require last-in, first-out behavior, such as undo and redo operations, recursive function calls, and expression evaluation. Queues are commonly used for operations that require first-in, first-out behavior, such as job scheduling, breadth-first search, and simulation. Here are some scenarios where you would...

Difference between a HashMap and a TreeMap in Java? Both HashMap and TreeMap are implementations of the Map interface in Java, but they differ in their internal implementation and performance characteristics. HashMap is an implementation of a hash table, which uses a hash function to calculate an index into an array of buckets, where each bucket contains a linked list of key-value pairs. The hash function is used to map each key to a unique bucket in the array. When a key-value pair is added to the map, the hash function is used to calculate the index of the bucket where the pair should be stored. The main advantage of HashMap is its constant-time performance for basic operations such as put() and get() on average. However, HashMap does not guarantee any order of the keys. On the other hand, TreeMap is an implementation of a red-black tree, which is a self-balancing binary search tree. In TreeMap , keys are sorted in a natural order or a custom order specified using a Comparat...

Garbage collector works in Java, and how can you control it? In Java, the garbage collector is responsible for automatically managing the memory used by the program, including deallocating memory that is no longer needed. Here's how it works: Allocation: When an object is created using the "new" keyword, memory is allocated for that object on the heap. Usage: The program can then use the object as needed. Identification: When the garbage collector runs, it identifies which objects are no longer being used by the program. This is done by looking at the object graph, which is a set of objects that reference each other. Marking: The garbage collector then marks each object that is still in use, starting from the roots of the object graph (such as static variables and the stack). Sweeping: The garbage collector then sweeps through the heap, deallocating memory for any objects that were not marked during the marking phase. Compaction: Finally, the garbage collector may also pe...