In this era, Java is one of the most popular languages to be known. Whereas there are more than nine million Java developers in the whole world, Java runs on more than 3 billion smartphones today. The increased demand for Java is an indication of its dominance in the software development field in the coming years. Now the question that arises is how do we prepare for the JAVA interview. The fact is that Java has some questions based on algorithms and data structure. In addition, the technical questions of java are more practical and use questions based on java programming. Moreover, the focus is on java concepts, API, and design patterns. There’s not a permanent method to prepare for Java interviews but knowing about the basic concepts of JAVA is most important as it is included in every method to crack the job interview for java. You can also take a course to learn java or else self-learning from the top books will also help. Apart from this, you can also work on projects as this will give you hands-on experience.
IMPORTANT TOPICS YOU CAN CHOOSE WHILE PREPARING FOR JAVA INTERVIEW
The ideal topics depend on the user’s experience and the job description.
In any case, you are applying for a core java multi-threading job application. In such a case you can focus on topics of core java like Generics, concurrency, multithreading, Enum, java collections, and JVM internals.
Similarly, if you are applying for a position in a java web application in that case you can prepare on topics like JSON, REST, SOAP, XML, and the other related topics of JAVA web Application it’s design and maintenance.
The one who is intended to crack an interview as a web app developer must practice on spring, JSP, and hibernate rather than focusing on JVM and Multi-threading units.
On the flip side, the Android developers should also know the Android API with the basics of Java
You should not stick to only common programming questions as someone who is a junior developer with 2 or 4 years of experience will witness questions on topics like fundamentals of JAVA, API, data structure, and Algorithms on the other side if it is the case of a senior developer who has an experience of 5 to 6 years he must get more questions on concurrency API, concurrent programming, GC Tuning, JVM internals, and the performance of JAVA. While a fresher would be asked questions on the fundamentals of Java-like string, collections, equals(), hashcode, and concepts of OOP
Whereas if you look at the interviews of JAVA EE and Core Java there is a lot of difference in it. The interview of core Java is more likely to focus on concepts like concurrency, JVM internals, and collections. While the JAVA EE interviews are more likely to be based on the framework like JSF, Spring, Hibernate, and others.
LIST OF IMP TOPICS FOR JAVA INTERVIEWS
- Fundamentals of java
- Data structure and algorithm
- Basics of thread, Multithreading, and concurrency.
- Array and string
- GOF design patterns
- JVM Internals
- XML processing in JAVA
- Basics of java
- Garbage collection
- Fundamentals and collection of data types
- Best practices of java
- Programming questions
- Junit
- Java IO and NIO
- Common networking protocols
- Abstract class and Inheritance
- Core Java
- API in java
- Abstraction and encapsulation
- Inheritance
You can also take help from the recommended books like “CRACKING THE CODING INTERVIEW AND JAVA EXPOSED” which is meant particularly for java interview questions; “A beginners guide” (junior developer);” Head First Java”. By this, you will get the idea of what questions you can expect from the interviewer if you are a fresher, junior developer, or a senior experienced developer. In this, there are questions asked in interviews of top MNC’s like Google, Facebook, and Investment banks like Citi, Morgan Stanley, and others.
That’s all you need to know when you are preparing for a java interview. You can narrow down deeper to some of the specific areas depending on the job description and specialization. If you are reading books daily and practicing consistently will make you confident to answer all the questions in the Java interview.
Some of the java interview questions
- Why is JAVA said to be a platform-independent programming language?
JAVA is both compiler & Interpreter based language. The interpreter (JVM) is available on any operating system that we install. The source code is compiled using the Javac compiler into byte code. This byte code is universal and can be converted into machine code that is why java is called a platform-independent programming language.
2 What is inheritance and why is multiple inheritance not supported in JAVA?
In the process of inheritance, the properties and functionalities of one class are acquired by another class. The purpose of inheritance is to provide the reusability of the code. The child class has to write only the unique features; the common properties and functionalities can be extended from a parent class. The multiple inheritances are only supported through interfaces only. As multiple inheritances lead to a deadly diamond problem so it is not supported
- What is an array in Java?
The length of the array is fixed when it is created. It is a container of the object that has a fixed number of items of a single type. The items are called elements and each element can be accessed by its numerical index. For example, let’s take 10 boxes from 0 to 9 in this case the 9th element can be accessed by the 8th element.
- What is garbage collection?
It is an automatic process in which the programmer doesn’t need to explicitly mark objects to be deleted. The implementation of garbage collection lives in the JVM. Each JVM can implement garbage collection.
5 Why is string Immutable in Java?
String objects are cached in the string pool. There is always a risk as the string literals are shared between multiple clients where the action of one client affects all another client. For performance reasons caching of string was important so this risk was avoided by making the string class immutable.
6 Can you explain the exception in JAVA?
During the execution of the program, an error occurs within the method. Then the throwing of an exception takes place in which the method creates an object (exception object) that contains information about the type and state of the program when the error occurred and then hands it over to the runtime system. The runtime system attempts to find out something to handle it. This something is the ordered list of methods called to get to the method when the error occurred this is called the call stack.
7 What is an applet in java?
It is a special kind of java program or a small java application that runs on a java-enabled browser. It is embedded inside a web page and then can be transported over the internet, and can be run as a part of the web document.
8 Why is performance better in StringBuffer than a string?
In string we cannot modify the content i.e. it is an immutable class. On the flipside in StringBuffer, we can change the content later. When performing simple concatenations, StringBuffer is faster than string. The character strings are routinely concatenated in string manipulation code. More Faster than StringBuffer is the string builder as it has no synchronization. As no extra overhead is added to the system it doesn’t slow down the processing.
Java OOPS questions
- Explain class in Java?
In object-oriented software, it is possible to have many objects of the same kind and share characteristics. It is called a class (A Software Blueprint)
- What is OOP?
The full form of OOP is an object-oriented programming system that is based on the concept of objects which contain data and methods. The purpose is to increase the flexibility and maintainability of the program. It brings together the data and its method into a single location named object which makes it easier to understand how a program works.
- Why can’t we create an abstract class in Java?
As the Abstract class contains abstract methods without body and output and is called an incomplete class so we can’t create an object of an abstract class.
Full-stack Java developers
If you rely only on the experience it will take you a long time to handle the full stack java concepts. The best way you can increase your performance is to use learn and apply methods. This will make you stand out from the people rather than having more experience and skills than you. ALSO one of the decisions you need to make is whether to have in-depth knowledge in few technologies with certifications, etc and present yourself as a full-stack developer and improve yourself with the experience and the ongoing learning. Coming to the technical interview part, the best way to plan it is to understand the problem, formulate a solution, explain it and then execute it.
Hope this article helps you a lot for understanding this topic. If you’re interested in free online courses with certificates, So enroll today on Great Learning Programme.
