ArrayList is a resizable array implementation of the List interface. It maintains insertion order, allows null and duplicate elements, and provides fast random access. However, its not thread-safe. Insertions and deletions in the middle of the list require shifting elements, making these operations...
Characteristics of Arrays Random Access: Elements can be accessed in O(1) time complexity using their index without needing to traverse the entire structure. Contiguous Storage: Arrays are physically and logically contiguous in memory. Fixed Size: Once initialized, an array's length is immutable. Ex...
The java.util.Collection interface serves as the root for all linear data structures in Java, branching into specialized subinterfaces: List for ordered sequences, Set for unique elements, Queue for FIFO operations, and Deque for double-ended access. ArrayList Internals ArrayList implements a dynami...
Java Collection Hierarchy The Java Collections Framework is divided into two primary branches to address different use cases: Single-column collections: Store individual elements. Double-column collections (Maps): Store key-value pairs. Collection Interface Fundamentals Key Interfaces and Implementa...
Core Collection Interfaces and Implementations List Implementations ArrayList provides a resizable array with O(1) random access performance: import java.util.ArrayList; List<String> items = new ArrayList<>(); items.add("first"); items.get(0); LinkedList offers a doubly-linked...
Exception Handling Exception Hierarchy Java exceptions are divided into two main categories: runtime exceptions (unchecked exceptions) and compile-time exceptions (checked exceptions), all inheriting from the Throwable class. throws Keyword The throws keyword is used at method declaration to indicat...