Top 7 Important java Questions to know for interviews
Java is a high-level programming language that was developed by James Gosling in 1982. It can be used to create complex programmes and is based on the ideas of object-oriented programming.

Important Java Questions to Know for Interviews


The numerous job opportunities that learning Java opens up are a significant factor for both beginners and professionals in the field of programming. The purpose served by this article is to prepare the career seeking enthusiasts/students for the interviews that deal in Java technicalities and ask questions pertaining to this subject matter. This will also guide you how to answer the most typical Core Java Interview questions.


Important Java Questions to Prepare Before Interviews

To improve your chances of succeeding in the interviews, go through all the questions. The questions cater to the principles of Java at the basic, core, and advanced levels. So let’s take a closer look at these important Java Interview questions and responses for both freshmen and experienced applicants.


  1. Java is a platform-independent language, why?


  The Java language was created in a way that it is independent of all hardware and software, and that is why, it becomes easy for the compiler to compile the code and then transform it to platform-independent bytecode that can be run on many platforms. The installation of a runtime environment (JRE) on the computer is the sole prerequisite for running that byte code.


  1. What's the difference between Heap and Stack Memory in java, and how does java utilize this?


– The memory space allotted to each distinct programme is known as stack memory. Heap memory, on the other hand, is the piece of memory that is not allotted to the Java programme but will be accessible to it when needed, often during the program's execution. Java makes use of this memory as


        All the variables, methods, etc. that we use when writing Java programmes are kept on the stack memory.

        Additionally, any object that is generated in a Java application is created in heap memory. And the stack memory was used to reference it.


  1. Is it true that Java is the full object-oriented programming language?


– We may assert that Java is a full-featured object-oriented programming language. Because classes are the foundation of Java. And therefore, attending the core classes, which are usually the foundational classes, is very important. Additionally, if we consider that Java supports primitive data types like int, float, char, boolean, double, etc., then we can argue that it is not a fully object-oriented programming language.


How much of an object-oriented programming language is Java, exactly? Java provides direct access to basic data types, hence we may conclude that it is not a wholly object-oriented programming language. Additionally, these basic data types are not directly a part of the integer classes.


  1. What distinguishes Java from C++?


        Java is both a compiled and an interpreted language, whereas C++ is simply a compiled language.

        A C++ programme can only execute on the system in which it was compiled, but Java programmes are machine agnostic.

        Users of C++ can utilize pointers in their programmes. Java, however, forbids it. Pointers are used internally by Java.

        Java does not support the idea of multiple inheritances, but C++ does. And the diamond problem is brought on by avoiding the complication of name ambiguity.


  1. In C/C++, pointers are employed. Why don't pointers exist in Java?


– Beginner programmers should avoid using pointers since they are fairly difficult. Java relies on writing simple code, therefore using pointers might be difficult. Potential faults can also be caused by pointer use. Furthermore, the usage of pointers compromises security since they allow users to directly access memory.


Thus, the absence of pointers in Java provides a certain amount of abstraction. Furthermore, the use of pointers may result in a delayed and inaccurate garbage collection process. Java uses references because, unlike pointers, they cannot be changed.


  1. What exactly does "data encapsulation" mean?


– In Object-Oriented Programming, the idea of data encapsulation refers to the concealing of data properties and associated behaviours within a single unit. By guaranteeing that each object is independent of other objects by having its own methods, properties, and functions, it aids developers in adhering to the modularity principle when creating software. It fulfills the objective of data concealing by being used to secure an object's private attributes.


  1. Describe the JIT compiler for us.


– JIT, or just-in-time, is a technique for enhancing run-time performance. It reduces the amount of time required for the code to compile by doing the process of compiling portions of byte code with identical functionality at the same time. The compiler merely converts source code into machine-readable code.



The aforementioned questions will definitely help attain the right career goal after a fulfilling interview. Java is used by over 9.6 million developers, and there's a strong reason for it even if it's not as novel and interesting as other languages like Python. Java is used in many desktop and mobile apps and is quite simple to learn. There are also a tonne of Java tools available that make it simple for novices and developers to utilize. Learning Java is often advantageous if you're thinking about a profession in computer science because hiring managers give preference to Java over other programming languages.


The ed-tech platform, Skillslash, for instance, serves the purpose of imparting knowledge on Java and educating and training the students on the same. Among various other core areas that can help professionals upskill, Skillslash also provides Java training under its modules. Popular courses from Skillslash to cater to this discipline of learning will be the Data Structures and Algorithms With System Design Program and the Full Stack Software Development course.