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Java is a high-level, object-oriented programming language known for its platform independence, strong typing, and extensive standard libraries.
JDK (Java Development Kit) contains development tools, JRE (Java Runtime Environment) runs Java applications, and JVM (Java Virtual Machine) executes bytecode.
Principles include encapsulation, inheritance, and polymorphism. Java uses classes and objects to implement these principles for building reusable and modular code.
Java compiles code to bytecode, which is executed by the JVM. Since the JVM is available on multiple platforms, Java code can run anywhere with a compatible JVM.
The "main" method is the entry point for Java applications. It receives command-line arguments and is invoked when the program starts.
Checked exceptions must be caught or declared, while unchecked exceptions (RuntimException) do not require explicit handling. Handling includes try-catch blocks or propagating exceptions.
Java provides the Thread class and Runnable interface for multi-threading. The "synchronized" keyword is used to create synchronized methods or blocks, ensuring thread safety.
JavaBeans are reusable software components with specific naming conventions, used for building software applications with graphical user interfaces (GUIs).
The "finalize" method is called by the JVM before an object is garbage collected. It allows an object to release resources or perform cleanup tasks.
Java handles memory management automatically through garbage collection. Manual memory management is not required, but developers should manage resources properly to avoid memory leaks.
Method overloading involves defining methods with the same name but different parameters. Method overriding is used to provide a specific implementation of a method inherited from a superclass.
The Collections Framework provides data structures like lists, sets, maps, and queues for organizing, storing, and processing data efficiently.
Custom exceptions are created by extending the "Exception" class. They help handle application-specific errors and provide meaningful error messages.
The "equals" method compares object contents, while "==" checks if two references point to the same object. For object equality, you should override the "equals" method.
Java provides JDBC (Java Database Connectivity) to connect to databases. Common libraries include Apache Commons DbUtils and Hibernate for Object-Relational Mapping (ORM).
"try-with-resources" automatically closes resources (e.g., files, streams) when the block exits, preventing resource leaks and simplifying exception handling.
Serialization is the process of converting Java objects into a byte stream. It's used for data persistence, network communication, and object sharing between applications.
Implementing an interface involves defining methods specified by the interface. Interfaces provide a contract for classes to follow, promoting code reusability and multiple inheritances.
JNDI is an API for accessing directory services. It's used for naming and directory operations in Java applications, such as looking up objects and resources.
Method chaining involves invoking multiple methods on an object in a single line, improving code readability. The builder pattern creates objects step by step, enhancing configuration flexibility.
The Stream API provides a concise way to process collections, enabling functional programming techniques like mapping, filtering, and reducing for data manipulation.
Annotations are used to provide metadata for classes, methods, and fields. Common Java annotations include "@Override," "@Deprecated," and "@SuppressWarnings."
The "assert" statement is used for testing assumptions during development. It helps detect errors by verifying whether specified conditions hold true.
Reflection allows you to inspect and manipulate class objects and their properties at runtime. It's appropriate for tasks like creating object instances from class names and accessing private fields.
I regularly read Java documentation, participate in Java forums, and explore online courses and tutorials. Experimenting with new Java features and personal projects helps me stay current.
The Java Memory Model defines rules for multithreaded memory access, ensuring consistent data visibility across threads.
Immutability means that objects cannot be changed after creation. It ensures predictable behavior, thread safety, and efficient caching in Java.
Use try-with-resources for automatic resource management. Close resources in the "finally" block to prevent resource leaks, following RAII principles.
Modularity involves breaking code into smaller, reusable components. Java supports modularity through packages, classes, and interfaces, promoting code reusability.
Check for null values before accessing objects to prevent "NullPointerException." Use Optional, null-safe methods, or default values where appropriate.
"@Override" indicates method overriding, "@Deprecated" marks obsolete code, and "@SuppressWarnings" suppresses compiler warnings. They provide metadata and improve code documentation.
JavaFX is a modern framework for GUI development, providing richer UI features, CSS styling, and better performance compared to Swing.
I use Git for version control. Branching strategies include feature branches, hotfixes, and pull requests for collaboration, while merging follows a clear review process.
"this" refers to the current object instance. It is used to distinguish instance variables from method parameters and to call constructors within other constructors.
Polymorphism is achieved through method overloading (multiple methods with the same name but different parameters) and method overriding (subclasses provide specific implementations).
A package is a namespace for classes, providing a way to organize and encapsulate code. It prevents naming conflicts and enhances code structure.
I use synchronization mechanisms like synchronized blocks or locks to protect critical sections of code from concurrent access in multithreaded applications.
The "hashCode" method returns a hash code for an object, while "equals" compares objects for equality. For custom classes, override these methods for proper object comparison.
Lambda expressions provide a concise way to define functional interfaces (single abstract methods) and simplify code for functional programming and stream operations.
Java supports asynchronous programming using features like CompletableFuture and Java's Executor framework. Libraries like Apache Camel and Akka provide advanced asynchronous capabilities.
JNI allows Java code to interact with native code written in C/C++. It is used when Java needs to access platform-specific or low-level functionality.
Profiling tools like VisualVM and YourKit help identify performance bottlenecks. Debugging tools like Eclipse or IntelliJ IDEA assist in diagnosing and fixing issues.
I use try-catch blocks for exception handling. Logging frameworks like log4j, Logback, or Java's built-in "java.util.logging" provide structured error logging.
Design patterns are reusable solutions to common software design problems. Examples include Singleton, Factory, Observer, and MVC patterns, used for improving code structure and maintainability.
Custom annotations are created by defining an annotation interface. They are used for metadata, documentation, or runtime processing, such as for unit testing and code generation.
The Servlet API allows developers to create dynamic web applications in Java. It handles HTTP requests, processes data, and generates responses for web clients.
I use threads, concurrency utilities, or asynchronous I/O to perform resource-intensive tasks without blocking the main thread. Thread pools and CompletableFuture are common choices.
Java's memory management involves allocating objects in the Young Generation, moving them to the Old Generation, and managing class metadata in PermGen or Metaspace.
Inheritance allows code sharing among classes, while composition involves creating objects with reusable components. Composition is favored over inheritance for better flexibility and avoiding tight coupling.
New Java versions introduce language enhancements, libraries, and improved performance. Java 8 introduced lambdas, while later versions offer better modularity, performance enhancements, and updated APIs. Staying current benefits developers with access to the latest features and security updates.