Topic Wise Java Interview Preparations

Basic Concepts (Covered Topics)

1. Basic Concepts
2. Object-oriented programming (OOP) principles: encapsulation, inheritance, polymorphism, abstraction.
3. Data types, variables, and constants.
4. Control structures: if, else, switch, loops (while, for).

Classes and Objects (Covered Topics)

1. Classes and Objects
2. Class definition, constructors, and instance variables.
3. Methods, method overloading, and method overriding.
4. Access modifiers: public, private, protected, package-private.
5. Static members: variables, methods, blocks.
6. Inheritance
7. Encapsulation
8. Polymorphism
9. Abstraction
10. Interfaces

Exception Handling (Covered Topics)

1. Exception Handling
2. Try-catch blocks.
3. Checked and unchecked exceptions.
4. Exception hierarchy and custom exceptions.

Collections Framework (Covered Topics)

1. Collections Framework
2. Lists, Sets, and Maps.
3. Iterators and Iterables.
4. ArrayList, LinkedList, HashSet, HashMap, etc.

Generics (Covered Topics)

1. Generics
2. Generic classes and methods.
3. Wildcards and bounded types.
4. Type erasure and limitations.

Multithreading and Concurrency (Covered Topics)

1. Multithreading and Concurrency
2. Thread creation and synchronization.
3. Synchronized blocks and methods.
4. Thread safety and deadlock.

Input/Output (I/O) (Covered Topics)

1. Input/Output (I/O)
2. File handling: reading and writing files.
3. Streams: byte streams vs. character streams.
4. Serialization and deserialization.

Memory Management (Covered Topics)

1. Memory Management
2. Garbage Collection: how it works and importance.
3. JVM memory structure: heap, stack, method area, etc.

Annotations (Covered Topics)

1. Java Annotations
2. Built-in annotations (@Override, @Deprecated, @SuppressWarnings).
3. Creating custom annotations.

Design Patterns (Covered Topics)

1. Singleton, Factory, Observer, Strategy, etc.
2. Understand when and how to apply them.

Java 8+ Features (Covered Topics)

1. Default methods in interfaces.
2. Optional class.
3. Stream API enhancements.

Lambda Expressions and Functional Programming (Covered Topics)

1. Syntax and usage of lambda expressions.
2. Functional interfaces.
3. Streams and operations like map, filter, reduce.

Java Virtual Machine (JVM) (Covered Topics)

1. How Java code gets compiled and executed.
2. JVM architecture and components.

Database Connectivity (Covered Topics)

1. JDBC (Java Database Connectivity).
2. Connection, Statement, ResultSet objects.

Unit Testing (Covered Topics)

1. JUnit framework.
2. Writing test cases and assertions.

String Manipulation (Covered Topics)

1. String class methods and immutability.
2. StringBuilder and StringBuffer for efficient string manipulation.

Enum Types (Covered Topics)

1. Creating and using enums.
2. EnumSet and EnumMap.

Advanced Data Structures (Covered Topics)

1. Queue, Stack, and their implementations.
2. TreeMap, TreeSet, LinkedHashMap, LinkedHashSet.

Advanced OOP Concepts (Covered Topics)

1. Abstract classes and interfaces.
2. Composition vs. inheritance.
3. Inner classes and nested classes.

Regular Expressions (Covered Topics)

1. Pattern matching using regular expressions (java.util.regex package).

Localization and Internationalization (Covered Topics)

1. Formatting dates, numbers, and currency.
2. ResourceBundle and related classes.

Java Memory Model (Covered Topics)

1. Understanding memory visibility and ordering.
2. Volatile and synchronized keywords.

Reflection (Covered Topics)

1. Class.forName(), newInstance().
2. Inspecting classes, methods, and fields dynamically.