The java.util.concurrent.atomic package in Java provides a set of classes that support lock-free, thread-safe operations on single variables. These classes are crucial for performance-sensitive applications where high concurrency is involved, as they allow multiple threads to operate on shared data without using explicit synchronization. Core Classes AtomicBoolean: A boolean value that may be updated atomically. …
The java.util.concurrent package in Java is a part of the java.util subpackages, introduced in Java 5. It provides a comprehensive set of concurrency utilities designed to simplify the development of multi-threaded applications and improve performance. The package includes classes and interfaces for thread management, synchronization, and coordination. Key Components of java.util.concurrent Executors framework The Executors …
java.util.Observer is an interface that represents the observer in the Observer design pattern. Objects that implement this interface can subscribe to an Observable object and be notified of any state changes. It works with java.util.Observable to implement the publish-subscribe model. Deprecated since Java 9 — replaced by modern event systems and reactive frameworks like Java …
java.util.Observable is a class in Java used to implement the Observer design pattern.It allows an object (observable) to maintain a list of dependents (observers) that are automatically notified of any changes in its state. Note: Observable is marked deprecated since Java 9 in favor of more flexible and customizable solutions like java.beans or third-party libraries …
java.util.Stack is a last-in, first-out (LIFO) data structure that extends the Vector class and is part of the Java Collections Framework. It models the classic stack data structure where elements are added and removed only from the top of the stack. Internally, since Stack extends Vector, it inherits all of its methods and characteristics, including …
java.util.Vector is a legacy class in the Java Collections Framework that implements a growable array of objects, meaning it can dynamically increase its size as elements are added. Introduced in the early versions of Java, Vector is synchronized, making it thread-safe by default. This means that only one thread can access the methods of a …
java.util.Hashtable is a legacy class in the Java Collections Framework that provides a data structure to store key-value pairs. It was part of the original version of Java and is based on the principle of a hash table, where each key is hashed internally to determine its storage location. A key feature of Hashtable is …
StringJoiner is a class introduced in Java 8 that helps in constructing a sequence of characters separated by a delimiter with optional prefix and suffix. This eliminates manual string concatenation and makes code cleaner and more readable, especially when formatting lists or reports. Commonly Used Constructors and Methods Simple Program Problem Statement LotusJavaPrince and Mahesh …
UUID (Universally Unique Identifier) is a class in java.util used to create unique identifiers that are 128-bit values, useful in distributed systems, databases, and unique object references. UUIDs are formatted as: Commonly Used Constructors and Methods Simple Program – Generate UUID Problem Statement LotusJavaPrince and Mahesh are managing a distributed document signing system for a …
java.util.Properties is a  subclass of Hashtable<Object, Object>.This is used to maintain lists of values in which both keys and values are strings.Ideal for configuration data like settings, messages, or environment variables.Often used to read/write .properties files in Java apps. Commonly used Constructors and Methods Simple Program Output Problem Statement: LotusJavaPrince and Mahesh are building a …
