Core Java Complete Notes By Durga Sir Top [new] Jun 2026

Use these notes as a textbook. Do not just read them; type out the code snippets, break them, fix them, and use the notes to understand why the compiler behaves the way it does.

Utilizing synchronized blocks or methods to prevent data inconsistency when multiple threads access shared resources simultaneously.

Allows null keys and values; it is unsynchronized and offers excellent lookup speed. TreeMap: Automatically sorts its keys in ascending order. core java complete notes by durga sir top

Durga Sir's notes contain explicit warnings regarding common pitfalls and tricky exam/interview questions. Highlight these sections during your revision cycles.

Designed for holding elements prior to processing, typically following a First-In-First-Out (FIFO) order. 2. The Map Interface Use these notes as a textbook

Threads communicate safely using .wait() , .notify() , and .notifyAll() . These methods must be called from within a synchronized context to avoid a IllegalMonitorStateException . 7. The Java Collection Framework

Inheritance promotes code reusability by letting a child class inherit properties and behaviors from a parent class. Java supports single and multilevel inheritance but bars multiple inheritance through classes to prevent the "Diamond Problem." Polymorphism Allows null keys and values; it is unsynchronized

Hiding implementation details using abstract classes and interfaces to focus on "what" the system does rather than "how." 5. Exception Handling

This structure transforms passive reading into active learning.

The package declaration must always be the first non-comment statement in a Java source file.