Java is one of the most popular programming languages in the world. It is a powerful and versatile high-level programming language based on Object Oriented Programming (OOP). To successfully navigate a Java technical interview, you should have a good grasp of OOP, data types, control structures, exception handling, etc.
We will discuss some of the common core Java interview questions and answers here.
The main characteristics of Java are:
It is platform-independent, which means it will run on any platform with a Java Virtual Machine (JVM).
It is based on the OOP (Object Oriented Programming) principles.
It is robust and secure due to its strong memory management, exception handling, and security features for prevention against malicious software.
It supports multithreading which means you can execute multiple threads simultaneously.
It supports dynamic loading of classes.
It is a high-performance programming language using Just-In-Time compilers.
A Just-in-Time or JIT compiler is a component of the Java Runtime Environment (JRE) that converts bytecode into machine code at runtime. Bytecode is the intermediate, platform-independent code produced by the compiler. The machine code is then directly executed by the CPU enhancing performance.
Inheritance is a concept in Object Oriented Programming that allows one class to inherit the properties of another. The class that inherits the properties is called a subclass or derived class. The class from which the properties and methods are inherited is called a superclass or base class.
A class is a blueprint or template that defines the properties and behavior of objects.
Objects are the instances of a class and represent a specific entity with a state and behavior as defined by the class.
JVM stands for Java Virtual Machine. It allows Java programs to run on different machines and operating systems.
JRE stands for Java Runtime Environment and provides the necessary libraries, JVM, and other components to run a Java application.
JDK stands for Java Development Kit and includes tools for developing, compiling, and debugging Java Programs.
A deadlock is set to occur in concurrent programming when one or more threads cannot execute because they are waiting for resources held up by another thread. This halts the system’s progress due to a cycle of dependencies unable to be resolved.
There are two different data types in Java. Primitive and reference data types. Byte, short, int, long, float, double, char, and boolean are the primitive data types. Whereas, classes, interfaces, arrays, and strings are reference data types.
These Java developer interview questions for freshers can be a good starting point for practicing and a good refresher of core concepts for experienced professionals. Keep practicing with more questions to get a step closer to your dream job in Java development.