15 Technical Core Java Interview Questions Answers for Experienced Developers

java interview questions for senior developer

The DatabaseMetaData interface returns the information of the database such as username, driver name, driver version, number of tables, number of views etc. It provides factory method that returns the instance of Connection. If a child class inherits the property from multiple classes is known as multiple inheritance. Java doesn’t use pointers because they are unsafe and increases the complexity of the program. Since, Java is known for its simplicity of code, adding the concept of pointers will be contradicting.

How to prepare for senior Java Developer interview?

  1. ArrayList vs LinkedList.
  2. REST vs SOAP.
  3. Merge vs rebase.
  4. Define the testing pyramid and its layers.
  5. How to sort HashSet of integers?
  6. Describe an exception hierarchy.
  7. How to identify performance issues in an application?
  8. How to handle huge data on Redis cache?

The New State represents a thread that has been created but not started yet. The Runnable state represents a thread that is ready to run but may not be scheduled to run by the operating System. The Blocked state represents a thread that is waiting for a monitor lock to be released.

It’s perfectly ok to check if candidate has ever used Date, Time and TimeZone features in Java or not. Given they are very important concept, you surely don’t want to overlook them. Continuous delivery (CD) is a software engineering approach where teams produce software in short cycles. It involves deploying changes to customers by clicking a button. Many teams use CD to ensure that they can release software anytime.

In contrast, wait() pauses the thread until a specified number of milliseconds has elapsed or until you call the notify() or notifyAll(). Essentially, the biggest difference is that wait() releases the lock or monitor while sleep() doesn’t release the lock or monitor while waiting. Some of the important methods of Java exception class are stated below. To create you own exception extend the Exception class or any of its subclasses.

Why is the remove method faster in the linked list than in an array?

WidgetParserImpl should be made static, and if it needs access to any of WidgetParserFactory’s internals, they should be passed into WidgetParserImpl’s constructor instead. This also makes it easier to extract WidgetParserImpl into a separate class should it outgrow its enclosing class. They are useful for performing initialization of complex static objects or to register a type with a static registry, as JDBC drivers do. The Java Classloader is the part of the Java runtime environment that loads classes on demand (lazy loading) into the JVM (Java Virtual Machine).

The term “this” is a particular keyword designated as a reference keyword. The “this” keyword is used to refer to the current class properties like method, instance, variable, and constructors. The add() and addAll() methods      are the main methods at the List interface. The add() method is used to add an element to the list, while the addAll() method is used to add a collection of elements to the list. A programme is a non-active entity that includes the collection of codes necessary to carry out a specific operation.

How to Implement MVC Architecture in Java?

Backpressure is a situation in which a data source produces data faster than a downstream consumer can process it. In Java, backpressure can be addressed using reactive streams, which allow https://trading-market.org/ downstream consumers to signal to upstream producers when they are ready to receive more data. To convert a JSON array to a List in Java, you can use a JSON library such as Jackson or Gson.

  • Also, for experienced java developer, Spring framework is must one.
  • These types of questions give you an excellent opportunity to elaborate more on showcasing your learnability skills.
  • Interviewers ask this question to ensure you have technical knowledge of Java, but also so to see how you can correct a team member’s work if needed.
  • It is the process of calling one constructor from another constructor in the same class.
  • The goal of this interview question is to check the previous experience of senior Java developer candidates, with a focus on how they propose new solutions instead of sticking to the plan.

However, with the proper guidance and preparation, there is a high possibility of conquering your next senior Java interview. So, in java you don’t have to worry about the memory management like CPP, It good to know who this works in java. Especially after java 8 changes where there is major updates regarding to it. What is parallel processing in java 8, what are the uses of it. Problem-solving skill is extremely critical for this function and with an example, you can understand how the candidate handles difficult situations. RDBMS stands for Relational Data Base Management System, which is based on the relational model of the database system.

During and post Interview

Having to hire Java developers with experience can be trying, especially if you’re a small startup with limited resources and connections. That’s why you need to ask incisive interview questions to narrow down the applicant pool. To help you get started, here are some sample junior- and entry-level Java developer interview questions.

Some examples of Structural patterns are Adapters, bridges, and Composites. Some examples of Creational patterns are Singleton, Factory, and Abstract Factory. No, we cannot change the scope of the overridden method in the subclass. The Object class is the only superclass for all classes in Java. ‘IS-A’ relationship is related to the Inheritance property of OOPs Java. It is a kind of parent-child relationship that is established between two classes.

java interview questions for senior developer

Java’s ‘write once and run anywhere’ nature is achieved by using Java Virtual Machine (JVM) and bytecode. Java code is compiled into bytecode, which can be executed on any platform that has a JVM installed. Because Strings are immutable, any change will result in the creation of a new String, whereas char[] allows you to set all of the elements to blank or zero. So storing a password in a character array clearly reduces the security risk of password theft.

Senior software engineers must understand how their code will function and which graphs to watch for overall system health. Good applicants will see the necessity for graphs or the addition of performance and debugging instrumentation to the code. However, not-so-good candidates will put it off or ignore it entirely. Strong applicants will instantly inquire about the existing system monitoring and instrumentation technologies in use. Being able to divide a huge class into smaller, more manageable classes is crucial for reducing the technical load that a team will have to deal with in the future. Senior software engineers must be able to gather requirements and ask questions to do so.

Garbage collection guarantees that a Java system runs properly and saves the programmer from having to perform it manually. The purpose of garbage collection is java interview questions for senior developer to make a system appear to have an infinite quantity of memory. When a system becomes sluggish, a garbage collector enters and gathers what is no longer in use.

50 Commonly Asked Full-stack Developer Interview Questions – InApps Technology

50 Commonly Asked Full-stack Developer Interview Questions.

Posted: Fri, 11 Nov 2022 08:00:00 GMT [source]

Sleep() is commonly used for polling and checking for results at regular intervals. Wait(), on the other hand, is better suited for multithreaded applications; used with notify() or notifyAll(), it can help achieve synchronization. Exception Handling is a cross-cutting concern and Spring provides @ControllerAdvice annotation that we can use with any class to define our global exception handler.

java interview questions for senior developer

However, they don’t say much about an applicant’s problem-solving abilities. This means that you can easily hire a Java developer who can’t apply their technical knowledge in real life. For instance, they may know how to use the Spring framework in theory, but when push comes to shove, they can’t use it to create a Java app. Check out the Java Training by Edureka, a trusted online learning company with a network of more than 250,000 satisfied learners spread across the globe.

Let’s take again an example of a relationship between House and rooms. House can contain multiple rooms there is no independent life of room and any room can not belongs to two different houses if we delete the house room will automatically delete. An aggregation is a specialized form of Association where all object has their own lifecycle but there is ownership and child object can not belong to another parent object. A single teacher can not belong to multiple departments, but if we delete the department teacher object will not destroy. Compile time polymorphism is method overloading whereas Runtime time polymorphism is done using inheritance and interface. When a method is declared final then it can’t be overridden by the inheriting class.

  • Stack memory in data structures is the amount of memory allocated to each individual programme.
  • This means that when we pass an object to a method, a copy of the reference to that object is passed, not the actual object.
  • Thus, this variable can be used only within the scope of a block.
  • The primitive and object and classes of Java, on the other hand, are not consistent.

The final keyword defines the entity which can be assigned only once and can’t be modified in the future. Once it’s been set, it can’t change its value anymore, for instance in the functions. The entity defined by the final keyword can be a variable, a class, a method, etc.

It loads bean definitions, wires beans together, and dispenses them if required. Also, it provides a generic way to load file resources, specific events to the beans defined as listeners, as well as means for resolving text messages using various languages. You can transform a Flux or Mono in Project Reactor using operators, which are functions that transform one reactive stream into another. Some common operators for transforming Flux and Mono include map(), flatMap(), filter(), and reduce(). Project Reactor is one of several reactive programming libraries in the Java ecosystem, including RxJava and Akka. Project Reactor is designed to be compatible with the Reactive Streams specification and can interoperate with other reactive programming libraries.

This software engineer interview question is particularly pertinent to senior-level roles. If you want someone with enough competence on your team, be sure they have previously taken care of projects and how they came out. This wide topic opens up a slew of debates and questions and gives a lot of information on how senior software engineer thinks and how effectively they can build a system. They may be more at ease with programming languages such as Clojure, Haskell, or Common Lisp if they come from a functional background.

Any statements within this static block of code will get executed at once while loading the class, even before creating objects in the main method. Compile-time type safety allows users to catch unnecessary invalid types at compile time. Generic methods and classes help programmers specify a single method declaration, a set of related methods, or related types with an available class declaration. The main function is called by the JVM even before the objects are created, thus even if the code correctly compiles, there will still be an error at runtime.

Equals() method is defined in Object class in Java and used for checking equality of two objects defined by business logic. Java is called platform independent because of its byte codes which can run on any system irrespective of its underlying operating system. As a Java professional, it is essential to know the right buzzwords, learn the right technologies and prepare the right answers to commonly asked Java Interview Questions. Here’s a definitive list of top Java Interview Questions that will guarantee a breeze-through to the next level. This is because an array is a contiguous block of memory where each element occupies a fixed amount of space. It is not possible by changing the return type in Java because the return type of a method is not part of its signature.

What should a senior Java Developer know?

  • Object-Oriented Programming Concepts. Object-Oriented-Programming.
  • System Design And Architecture. System Design and Architecture.
  • JVM Internals.
  • Java Build Tools.
  • Web Technologies.
  • Code Version Control.
  • Java Testing Tools.
  • Web Frameworks.

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