Important Topics

• Kunal's notes
• Object Oriented Paradigms GFG
• Constructors in Java GFG
• Constructor chaining in Java GFG
• Inheritance in Java GFG
• Overriding in Java GFG
• Abstraction in Java GFG
• Access modifiers in Java GFG
• Wrapper Classes in Java GFG
• Need of wrapper classes in Java GFG
• this keyowrd in Java Javatpoint
• Important keyowrds in Java inheritance - extends,implements,super,instanceof Tutorialspoint
• Instance initializer block Javatpoint
• Dynamic Method Dispatch or Runtime Polymorphism in Java GFG
• Cohesion in Java GFG
• Coupling in Java GFG

Interview Questions

• Can we declare main() method as private or protected or with no access modifier in java? Tutorialspoint
• Difference between Method Overloading and Method Overriding in Java? GFG
• Can we declare interface members as private or protected in java8? Tutorialspoint
• Can we override a private or static method in Java? Tutorialspoint
• What is diamond problem in Java? Javatpoint
• Can we pass this keyword as argument in a method call? Javatpoint
• Java constructor returns a value, but what? Javatpoint
• What is covariant return type? Javatpoint
• Private classes and singleton classes in Java GFG
• How to prevent Singleton Pattern from Reflection, Serialization and Cloning? GFG
• Double-Check Locking For Singleton Class GFG

Practice Problems

• Inheritance I HackerRank
• Inheritance II HackerRank
• Java Abstract class HackerRank
• Interface HackerRank
• Method Overriding I HackerRank
• Method Overriding II (Use super keyword) HackerRank
• Java instanceof keyword HackerRank
• Java Iterator HackerRank