Java interview questions?
- What is Java?
Java is a high-level programming language that is designed to be portable, robust, and secure. It is used to develop a wide range of applications, from mobile apps to enterprise-level web applications.
- What are the main features of Java?
The main features of Java are:
- Platform Independence
- Object-Oriented Programming (OOP) concepts
- Robustness
- Security
- Portability
- High performance
- What is JVM?
JVM stands for Java Virtual Machine. It is an abstract machine that provides the runtime environment for Java programs to run. JVM is responsible for interpreting the compiled Java code and executing it.
- What is the difference between JDK and JRE?
JDK (Java Development Kit) is a software development kit that provides the tools and APIs necessary to develop Java applications. JRE (Java Runtime Environment) is the environment required to run Java programs.
- What is the difference between an abstract class and an interface?
An abstract class is a class that cannot be instantiated and is designed to be subclassed by other classes. It may contain both abstract and non-abstract methods. An interface is a collection of abstract methods and constants that can be implemented by any class.
- What is a package in Java?
A package is a collection of related classes and interfaces. It is used to organize Java code and make it easier to manage and maintain.
- What is the difference between a checked and an unchecked exception?
A checked exception is a type of exception that must be declared in the method signature using the "throws" keyword. It must be caught or declared to be thrown by the calling method. An unchecked exception is a type of exception that does not need to be declared or caught.
- What is multithreading in Java?
Multithreading is a programming technique that allows multiple threads of execution to run simultaneously within a single program. In Java, multithreading is implemented using the Thread class or the Runnable interface.
- What is a synchronized method?
A synchronized method is a method that can only be accessed by one thread at a time. It is used to prevent race conditions and ensure thread safety in multi-threaded programs.
- What is the difference between a StringBuilder and a StringBuffer?
StringBuilder and StringBuffer are both classes used to manipulate strings in Java. The main difference between them is that StringBuilder is not thread-safe, while StringBuffer is. StringBuilder is faster than StringBuffer because it is not synchronized.
Comments
Post a Comment