Core Java is a popular programming language that is widely used for developing enterprise-level applications. If you are planning to appear for a Java developer interview, you must be prepared to answer a wide range of Core Java interview questions. In this blog post, we have compiled a list of some of the most important Core Java interview questions that you should know to increase your chances of getting hired.
- What is Java?
Java is a high-level, object-oriented programming language that is designed to run on any platform without the need for recompilation. It was developed by James Gosling at Sun Microsystems in the mid-1990s.
- What are the main features of Java?
Java is known for its simplicity, object-orientation, portability, security, and platform independence. These features make it a popular choice for developing enterprise-level applications.
- What is the difference between an interface and an abstract class in Java?
An interface is a collection of abstract methods that can be implemented by a class, while an abstract class is a class that cannot be instantiated and can contain both concrete and abstract methods. Additionally, a class can implement multiple interfaces, but can only inherit from one abstract class.
- What is the difference between a compiler and an interpreter in Java?
A compiler translates source code into machine code, while an interpreter executes source code line by line. Java uses both a compiler and an interpreter, with the Java compiler translating source code into bytecode and the Java Virtual Machine interpreting the bytecode at runtime.
- What is the difference between static and non-static methods in Java?
Static methods belong to the class and can be accessed using the class name, while non-static methods belong to the object and can only be accessed through an instance of the class.
- What is the difference between a HashMap and a TreeMap in Java?
A HashMap is an unordered collection that stores key-value pairs and uses hashing to store and retrieve elements, while a TreeMap is an ordered collection that stores key-value pairs and maintains elements in sorted order.
- What is the difference between an ArrayList and a LinkedList in Java?
An ArrayList is an ordered collection that allows fast access to elements using an index, while a LinkedList is an ordered collection that allows fast insertion and removal of elements.
- What is the difference between method overloading and method overriding in Java?
Method overloading is when a class has multiple methods with the same name but different parameters, while method overriding is when a subclass provides a new implementation of a method that is already defined in its superclass.
- What is the difference between a thread and a process in Java?
A process is an instance of a program that is being executed, while a thread is a lightweight unit of execution within a process. Multiple threads can be executed within a single process.
- What is the purpose of the Java Virtual Machine?
The Java Virtual Machine is responsible for executing Java bytecode and providing a platform-independent environment for Java programs to run. It also provides memory management and garbage collection