Java Interview Questions And Answers For Freshers

Java has been around for more than 20 years and is still useful for millions of programmers. With its ever-increasing popularity, the Java programming language has a lot of job opportunities.  

Several top companies rely on Java because of its capabilities and performance, including Uber, Spotify, Google, Instagram, Netflix, Amazon, and many others. Most tech companies demand that job candidates have a solid understanding of Java and its frameworks. So, if you want to work for any of these companies, you must be proficient in Java programming. 

If this is your first job using Java, preparing for your interview ahead of time can be helpful. Preparing possible interview questions beforehand is one approach to achieving this.  Being prepared for potential Java-related interview questions will boost your confidence and perhaps improve your chances of getting the job. 

For freshers, getting ready for a Java interview might be stressful, particularly if you don’t know what to look for. Are you trying to find interview questions for Java? Our goal is to help you become a better Java programmer by providing you with 20 common Java interview questions and answers for freshers. 

Let’s start with understanding what Java is all about!

What Is Java?

Java is a frequently used programming language in the field of software development.  James Gosling invented it in 1995 while working at Sun Microsystems. Java is used to create several types of applications, such as business systems, web-based applications, as well as applications for smartphones and desktops. 

Most developers chose Java as their very first programming language since its syntax is basic and pretty simple for beginners. Candidates used to obtain a Java certification from a renowned Software Training Institute in Chennai to enhance their proficiency and expertise. 

Java has a syntax similar to English and uses just a few special characters, making it easy to learn in a short amount of time. It is derived from an ancient language that has been greatly impacted by C++, so mastering these languages will open up a wide range of professional possibilities. 

Oracle released a report stating that 97% of enterprise desktops and laptops run Java. One of the reasons Java is still important is because its enterprise adoption rate has consistently been high and stable. 

To know more about Java programming, read on What Is Java? – Java Programming Language Explained!

Java Interview Questions For Freshers:

The following are some common questions an interviewer might ask a fresher about Java:

1. Is The Java Platform Independent, And If So, How?

Yes, the Java language is platform-independent. The Java compiler builds the program’s code into a byte code or .class file, in contrast to many other programming languages. The bytecode can operate independently of any hardware or software, but to continue executing the bytecode, the operating system must have a JVM (Java Virtual Machine) file preloaded. 

2. Which Operating Systems Will The Java Programming Language Support?

Many operating systems, including Windows, Mac OS, and other UNIX/Linux versions, including Sun Solaris, HP-Unix, Ubuntu, Redhat Linux, CentOS, etc., can execute Java. 

3. What Features Does Java Have?

Java is a widely used programming language because of several characteristics. The most common features are platform independence, self-supporting memory management, object-oriented programming, adaptability, and security. 

4. What Distinguishes C++ And Java?

• Java is an interpreted language in addition to being compiled, while C++ is solely a compiled language. 
• While C++ programs can only operate on the system in which they are compiled, Java programs are machine-independent. 
• Pointers can be used within programs written in C++. However, Java prohibits it. Java makes use of pointers internally. 
• Java does not allow the concept of multiple inheritances, while C++ does. 

5. What Exactly Is An Interface In Java? Give An Example.

In Java, an interface is a group of abstract constants as well as methods that any type of class may execute. For example, the Comparable interface provides the compareTo() function for object comparison.

6. How Can A Quick Sort Algorithm Be Implemented In Java?

You can create a quick sort algorithm in Java using recursion and a partition method to split the array into two sections. 

7. What Are The Various Variables In Java? 

In Java, there are primarily three categories of variables. They are as follows: 

Static Variables: A variable is referred to as static if it has been defined with the static keyword. A static variable can only have one memory allocation and cannot function as a local variable. 

Local Variables: A variable is considered local if it is defined inside the body of the class function. With the static keyword, local variables cannot be declared.

Instance Variables: An instance variable is a variable that has been defined within the class but not inside the body of the method. The value of this variable is instance-specific and cannot be shared with other variables and it cannot marked as static.

8. What Memory Allocation Options Does Java Offer?

There are five main types of memory allocations in Java.

• Class Memory
• Stack Memory
• Heap Memory
• Native Method Stack Memory
• Program Counter-Memory

9. Explain The Copy Constructor In Java?

Copy constructors are constructors that initialize a class object with the help of another object of the same class.

10. Describe The Java String Pool?

Java String Pool is the name given to a group of strings stored in Java’s Heap memory. Before creating a new string object, JVM (Java Virtual Machine) makes sure the item already exists in the pool. The variable uses the same object reference, if accessible, or creates a new one if not.

11. What Is The Final Keyword In Java?

In Java, the keyword “final” has been predefined and used when assigning values to variables. When the final keyword is used to declare a variable, its value remains constant during program execution.

12. What Types Of Constructors Are Available In Java?

The Java constructors have been divided into two categories depending on the parameters that were passed:

Default Constructor: The constructor that is default does not take any values. It is mainly used to initialize instance variables with default values. Furthermore, it can carry out useful tasks based on the creation of objects. 

Parameterized Constructor: In this constructor, instance variables are initialized with given values. In other words, this constructor can receive parameters.

13. Why Does Java Use The Unicode System?

Due to the issue with earlier language standards, the Unicode system was introduced. The International Standard Character Encoding, or Unicode, is used to represent the majority of languages written worldwide. Since Unicode provides a default character size of two bytes, Java uses Unicode because it only needs two bytes for each character. 

14. What Prevents Java From Being A Pure Object-Oriented Language?

Since Java can handle primitive data types like byte, char, short, boolean, int, long, float, and double, it cannot be considered a fully object-oriented language. 

15. What Is Typecasting?

• In Java, typecasting is a specific programming technique used to change one data type into another. 
• Converting a smaller data type to a larger data type is known as “widening”.   Eg – byte -> short -> char -> int -> long -> float -> double. 
• Similarly, converting a larger data type to a smaller data type is known as “narrowing.”  E.g. – double -> float -> long -> int -> char -> short -> byte. 

16. What Are The Different Types Of Operators In Java?

Java offers eight different types of operators, which are as follows:

• Arithmetic operators
• Logical operators
• Assignment operators
• Bitwise operators
• Relational operators
• Unary operators
• Ternary operators
• Shift operators

17. What Does Java Operator Precedence Mean?

To specifically define the sequence in which operators are evaluated, Java offers a set of guidelines. The operator precedence is applied if the expression contains a large number of operators. The operators in the expressions are evaluated according to their priority by this operator precedence. For instance, in comparison to addition and subtraction, multiplication is given priority.

18. How Many Logical Operators Are There In Java? 

In Java, logical operators can be classified into three categories: 

• Logical NOT: This operator can be applied to boolean type variables, relational variables, and logical expressions. Its symbol is “!”. 
• Logical OR: This sort of logical operator only works with boolean variable types, and its symbol is “||.”
• Logical AND: This operator allows us to bring together a variety of relational operations, and the result will be of the boolean type. Logical AND is represented by the symbol “&&”.

19. When Is The Super Keyword Used?

If a method in a class works similarly to a method in its parent class, you can use the keyword “super” to represent the parent class method. Additionally, it describes a hidden field.

20. What Exactly Is An Applet?

An applet is similarly like a Java program that works inside a web browser. It can do a lot of things just like any other Java program because it has access to the whole Java toolkit. 

Conclusion

Thus, we’ve covered the top 20 Java interview questions for freshers. In fact, your chances of succeeding in the interview will only rise depending on how many questions you answer.

Moreover, having a certification helps you ace the interview. Therefore, if you have not yet demonstrated your Java proficiency, we recommend enrolling in Java Training in Chennai to initiate your certification preparation as soon as possible.

In conclusion, you will be successful in obtaining your ideal career if you continue to study and hone your Java skills. Best of luck!