Polymorphism means "many forms." It allows one interface to be used for a general class of actions.
| Concept | Arrays | Collections | | :--- | :--- | :--- | | | Fixed in size; you cannot change size after creation. | Growable in nature; size can be increased or decreased as needed. | | Memory | Not memory efficient; if size is unknown, memory may be wasted. | Recommended to use as memory is allocated dynamically based on requirements. | | Performance | Performance-wise recommended as they store data in a contiguous memory location. | Performance-wise not as good as arrays. | | Data Types | Can hold only homogeneous data type elements. | Can hold both homogeneous and heterogeneous elements. | | Structure | No underlying data structure; no readymade method support. | Every collection class is implemented based on a standard data structure, providing rich, ready-made method support. |
catch : Handles the specific exception thrown in the try block. core java complete notes by durga sir top
If you are tired of watching 15-minute YouTube tutorials that leave you more confused, or reading heavy textbooks that dry your eyes after 10 pages, give these notes a try. Print them out (if you get the PDF). Grab a highlighter. Write your own margin notes. Hand-code every example.
OOPs is the most critical module in Durga Sir's notes. He moves away from generic book definitions and explains OOPs through real-world system design. The Four Pillars of OOPs Polymorphism means "many forms
Can have both abstract methods (without bodies) and concrete methods. They cannot be instantiated.
Encapsulation is the practice of binding data fields with the methods that operate on them. | | Memory | Not memory efficient; if
┌──────────────┐ │ Collection │ └──────┬───────┘ ┌───────────────┼───────────────┐ ▼ ▼ ▼ ┌───────┐ ┌───────┐ ┌───────┐ │ List │ │ Set │ │ Queue │ └───────┘ └───────┘ └───────┘ 1. Core Interfaces
Declared in a method signature to warn callers that the method might throw specific exceptions. Module 4: Multi-Threading
: Utilizes wait() , notify() , and notifyAll() methods from the Object class to let threads coordinate states safely, preventing race conditions. 7. Java Collection Framework
