50+ Top L&T Interview Questions With Answers That You Should Not Skip

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L&T is one of the most prestigious companies known for dealing in different sectors. It is no surprise that L&T is among the dream companies for many candidates to work for due to its employee perks and working environment. Here we are sharing a list of technical and HR questions for an L&T interview that you must know about.

L&T Infotech Recruitment Process: An overview

In comparison to other firms, the most recent interview procedure followed by L&T Infotech is marked by a few notable distinctions. We will guide you through the L&T Infotech Interview process 2022 and help you grasp its requirements. You should review the L&T HR interview questions to avoid poor HR interviews that we have provided for you in addition to the L&T infotech Java technical interview questions for recruitment. Here is the total number of rounds at L&T-

1. Screening round
2. Technical interview rounds
3. HR interview round 

List of technical questions for L&T infotech interview

Here is a list of technical interview questions that we have compiled after a comprehensive search; these are the top technical questions that could be faced during an L&T interview.

1. What are the functions of database management systems?

A database management system, often known as a DBMS, is a piece of software that provides users with the ability to manage databases efficiently. Users are granted the ability to access as well as interact with the data that is stored beneath the database's surface. Such actions might range from just querying the data to designing database schemas that significantly impact the structure of the database. You can also use logical database independence for different projects. You can also make different alternative query processes for optimizing the project. The query optimizations are necessary in some cases. However, an unoptimized query can cause problems.

2. What is the return type value?

Whenever a function is finished carrying out its designated mission, at that point it sends the script or another function that calls it a value known as a return. Any one of the following sorts of variables could be used as a return value: handle, integer, object, or string. The nature of the value that is returned by your function is heavily influenced by the task that it is responsible for.

3. What are the 4 access modifiers?

To put it simply, there are four different kinds of access modifiers: public, private, protected, as well as default (no keyword). Before we get started, let's make a note that the only access modifiers that a top-level class could use are public or default. We have access to all four of these options at the member level.

4. What is the Fibonacci series using recursion Java?

The Fibonacci numbers are a well-known mathematical sequence where each subsequent number is calculated by adding the two numbers that came before it. Using a recursive approach, one can determine the value of the Fibonacci series number that corresponds to a specific place in the sequence.

5. What is a primary key vs. a foreign key?

The use of a primary key is what ensures that each piece of information contained within a certain column is one and alone. A column or combination of columns in a relational database table which establishes a connection between the information contained in two different tables is known as a foreign key. A record in the relational database table can be identified by this attribute in a manner that is unique.

6. Why do we need a super key?

In simplest terms, the function of the super key is to identify the tuples that are contained within the database table that have been defined. It is known as the superset, in which the candidate key appears solely as a component of the super key. Therefore, all of the attributes in a table that are in a position to identify every one of the other attributes within the table in an unambiguous fashion constitute the super keys for that table.

7. What are the absolute path and relative path?

The act of stating the location of a file or directory relative to the root directory (/) is what is meant to be understood as using an absolute path. To put it another way, we can say that such an absolute path is a comprehensive path beginning with the directory / at the beginning of the actual file system. The term "relative path" refers to the path that is immediately related to the work that is being done at the present moment (PWD). It never precedes the first directory with a / and always begins at the directory you are currently in.

8. What does the path variable contain?

The path variable stores a list of directories that the operating system navigates through before carrying out a command. By bringing the path variable up to date, you would be able to launch any executables that can be found in the directories that are specified in the path variable from every directory without having to type the absolute file path.

9. What is software testing?

The method of evaluating & validating that a software product or application performs the tasks for which it was designed is referred to as software testing. The elimination of bugs, a reduction in the amount of money spent on development, and an increase in performance are all results of testing.

10. What are generic functions in Java?

Java's generic functions are similar to methods in other programming languages in that they accept a parameter and afterward return some value after completing an action. It is precisely the same as a regular CPU function, with the exception that a generic method has type parameters that are referenced by the actual type. The generic approach can now be utilized in a manner that is more general, thanks to this.

11. What does memory management do?

Memory management or memory manager is a component of an operating system that is responsible for managing a computer's primary memory, in particular RAM (Random Access Memory). In this manner, memory management is required to carry out a wide variety of tasks to grant the processing units access to program data and code, which is necessary before the processing units may carry out any procedures. A memory manager is an essential part of programming. 

12. What are SQL queries?

SQL queries are indeed the instructions that are employed to perform actions, CPU functions, as well as queries with data. They are used to interface with a database to carry out these activities. SQL queries could be utilized to do a variety of tasks, including searching the database as well as creating tables, adding data to tables, changing data, as well as dropping tables. Single query functions are helping us perform some tasks. 

13. What is a singleton class?

In Java, a singleton class can only contain one instance, and as a result, all of its methods & variables are associated with that one instance alone. The idea of a singleton class is helpful in circumstances in which there is a requirement to restrict the total number of objects belonging to a class.

A situation in which there is a limit of having just one connection to a database as a result of some driver constraints or as a result of any licensing difficulties is the greatest illustration of a possible scenario for using a singleton.

14. What's the difference between an interface and an abstract class?

The major distinction between being an abstract class and an interface is that the latter interface can only include declarations of public static methods and cannot contain any concrete implementation, whereas an abstract class can now have members with just about any access specifiers (public, private, etc.) and can contain or not have concrete implementation. In other words, an interface can only contain public static method declarations.

Another significant distinction between the use of abstract interfaces and classes is that the class which enforces an interface is required to implement every one of the methodologies of the interface, whereas a class that inherits from such an abstract class is not required to implement every one of the methods of its superclass. This distinction is one of the most important aspects of the usage of abstract classes and interfaces.

However, a class is only allowed to extend a single abstract class even if it implements more than one interface.

15. What are the advantages of inheritance?

One of the most significant advantages of utilizing inheritance is the increased potential for code reusability. This is because inheritance makes it possible for sub-classes to reuse the code of their superclass. Polymorphism, also known as extendibility, is yet another advantageous feature that makes it possible to add new functionality without negatively affecting classes that have already been derived.

16. What are "object-oriented programming languages"?

Object-oriented programming languages, sometimes known as OOP languages, are a paradigm for computer programming that focuses on objects instead of CPU functions. It isn't a tool or a programming language; rather, it is a paradigm that was meant to address the faults of procedural programming. This paradigm was designed to be used in object-oriented programming languages. Various programming languages adhere to OOP language principles; some of the most well-known examples are Java, Python, and Ruby, among others. Several frameworks follow OOP language principles, and one such framework is Angular.

17. What are Java's Local variables and Instance variables?

Local variables are variables that can only be accessed within the method or code block in which they were defined. This makes them inaccessible to other parts of the program. On the contrary hand, all of a class's methods have access to the instance variables that belong to that class. Local variables, on the other hand, can be defined anywhere within a method or a code block; however, instance variables can only be declared within a class and not within a method. Instance variables always have a value, even when they are not assigned one; this value can be null, 0, 0.0, or false.

This is not the case with local variables, which must have a value assigned to them to function properly; if a value is not assigned, then an error will occur. Whenever a method is invoked, local variables are instantaneously generated and then discarded as immediately as the method completes its execution. It is necessary to make use of the new keyword while generating instance variables.

18. What are the "Abstract class" and "Abstract method"?

In Java, a class that cannot be instantiated is referred to as an abstract class. Implementing the abstract methods and then either overriding or using the implemented methods indicated in the abstract class are both frequent uses for a class of this type. Subclasses are typically extended using the base class provided by this type of class. It is necessary to use the abstract keyword after the class name to construct an abstract class. Any abstract class may contain either abstract or non-abstract methods. Neither one is required. An abstract method is a method that just has a declaration rather than the implementation in the Java programming language. In addition, the abstract keyword comes right after the name of an abstract method. Any practical subclass which extends the abstract class is obligated to supply a representation for any abstract methods that they inherit.

19. What is the difference between using the throw keyword and the throws keyword?

The throw keyword is employed to deliberately throw an exception, whereas the throws keyword is used to declare exceptions that can be thrown. It is not possible to propagate verified exceptions using throw alone, but throws make it possible to do so without the requirement for anything more. The throws keyword comes after a class, while the throw keyword comes after an instance. The throws keyword is more common. The throw keyword has been used while the method itself is being executed, whereas the throws keyword is used when the method signature is being generated. In addition, it is not allowed to throw several exceptions at the same time; nevertheless, it is feasible to declare many exceptions at the same time.

20. What is the priority queue and alternative query in Java?

In contrast to a standard queue, a priority queue is indeed an abstract data type that assigns a priority to each item it holds. Priority queues are similar to normal queues in other respects. When there is a priority queue, the element that has the highest priority gets served before the one that has the lowest priority. Element placement in a priority queue can be determined either by the comparator or by the order of nature of the elements. The order in which elements are placed within a priority queue reflects the relative importance of those elements. Talking about the alternative query they are used to specify queries to SQL. 

21. What is "reflection" when talking about Java?

The Reflection application programming interface (API) allows for the examination and modification of the running behavior of different classes, interfaces, and methods. Java Reflection is a highly effective technology that has the potential to bring about a variety of positive outcomes. Through the use of “Java Reflection”, it is possible to do runtime analysis of classes, interfaces, fields, as well as methods without having prior knowledge of the names given to these elements during the compilation process.

Reflection's many applications include the creation of new objects, the invocation of methods, as well as the retrieval and setting of field values. The use of external, user-defined classes is possible by first generating examples of extensibility objects and then giving those instances the fully-qualified names of the classes in question. Debuggers also have the option of using reflection to investigate the private members of classes.

22. What is a "JIT compiler" in Java?

In Java, the term “Just-In-Time compiler” (JIT) refers to this type of compiler. It is a program that assists in the process of translating the Java bytecode into instructions which are then transmitted directly to the processor. The JIT compiler is turned on even when a Java method is called, as it is enabled by default in Java and engaged automatically in these situations. After that, the bytecode of the method that was invoked is transformed into native machine code by the JIT compiler, which does this transformation "just in time" before the method is executed. After the method has indeed been compiled, the JVM will directly call the code that was compiled for that method instead of interpreting the code that's been originally written. Because of this, it is frequently tasked with the responsibility of optimizing the performance of Java programs while they are running.

23. What is "aggregation"?

Aggregation is a more sophisticated variation of the Association data structure, in which each item has its lifespan, but there is ownership, as well as class child objects, that cannot belong to more than one parent object. Take the instance of the department and the teacher, for instance. Although a single teacher cannot be a member of more than one department, the object of the teacher won't be destroyed if the department in which they are employed is deleted.

24. Can you explain "composition" when talking about Java?

The link between composition and aggregation is what we can refer to as a "death" relationship. Composition is just a more sophisticated version of aggregation. This particular form of Aggregation is powerful. Method of child class objects do not have their life cycles, and when the lifecycle of their parent object is erased, all of its class child objects will likewise be deleted. Let's take a closer look once more at an illustration of how the House is related to its rooms. There's no such thing as an independent life of a room, as well as a room cannot be part of two separate houses at the same time. If we eliminate the house, all of the rooms within it will also be deleted immediately.

25. What is the “Hibernate Framework''?

Object-relational mapping, more commonly abbreviated as ORM, is a programming approach that maps relational database tables to application domain model objects. ORM technology is based on Java and provides a framework for mapping domain knowledge objects to relational database tables & vice versa. Hibernate is indeed an example of an object-relational mapping utility.

Because it offers a reference implementation of the “Java Persistence API,” hibernate is a fantastic option for an ORM tool, and it also delivers the advantages of low coupling. CRUD operations are something that we can accomplish with the help of the Hibernate persistence API. Using JPA annotations and XML-based setup, the hibernate framework gives users the ability to map plain old Java objects to conventional database tables. This may be done by using the mapping feature.

In a similar vein, hibernate configurations are adaptable and may be altered either programmatically or through the use of an XML configuration file.

26. What is the key distinction between an error and an exception?

An error is a condition that cannot be recovered from what takes place during the runtime. An example of this would be an “OutOfMemory'' issue. It is not possible to rectify these JVM problems while they are being processed. Even though errors can be detected in the catch block, the execution of the application will be halted, and there will be no way to recover from the problem.

Exceptions, on the other hand, are conditions that come about as a result of things like incorrect input or mistakes made by humans, etc. For example, the “FileNotFoundException” exception should be thrown if the file that was specified cannot be located. If you try to use a null reference, you will encounter an error known as a “NullPointerException”. In the majority of instances, it is possible to recover after an exception (often by providing the user with feedback on whether or not they entered the correct numbers, etc.).

27. What does synchronization mean?

The term "synchronization" actually relates to the practice of "multi-threading." Only one of the threads in the program can run a synchronized block of code at any given moment. Given that Java allows for the execution of many threads, two or more threads can access the same fields or objects at the same time. A procedure known as synchronization ensures that all of the threads that are now being executed concurrently are in sync with one another. Memory consistency faults, which can be generated when there is an inconsistent view of a shared contiguous memory location, can be avoided by the usage of synchronization. When a method is defined to be synchronized, the monitoring of the object that corresponds to that method is taken care of by the thread. The thread will remain stopped until the other thread that is running the synchronized method releases the monitor.

28. What is the "static method"?

You don't need to create an instance (Object) of the class to call static methods; they can be called directly instead. A static method has immediate access to all of a class's static variables, but it is unable to access a class's non-static variables until an example of the class is first created.

29. What exactly is meant by the phrase "static import"?

It is possible to use members (fields & methods) that are zoomed within their container class as public static in Java code, thanks to a feature called static import that was introduced within the Java programming language. This feature allows for the use of members in Java code without having to specifically define the class where the field was defined. Version 5.0 of the language has this functionality, which was initially included in earlier versions.

30. What do you know about "Java Bean"?

A Java class is said to be "JavaBean" if it adheres to a series of simple rules, one of which is a set of conventions just on names of particular methods to retrieve and set state, which is known as "Introspection." Because it adheres to norms, it can be simply handled by a software package that brings Beans together and at runtime. This is due to the conventions it adheres to being well established. “JavaBeans” are reusable software elements created in the Java programming language.

31. Where is the function Object() { [native code] }?

The function Object() { [native code] } is a specific kind of method that is employed to set the state of an object to its default value. It is possible to think of it as the method that "builds" the object. It is called whenever the class is instantiated, which is also the time when the memory for execution of the object is made available. When an object is formed with the new keyword, the class's default function Object() { [native code] } is invoked. This happens every time an object is created. It is required that the name of the function Object() { [native code] } be somehow related to the name of the class. It is not permissible for the function Object() { [native code] } to have an explicit return type.

32. What does encapsulating mean?

Encapsulating data refers to the practice of combining data and programming logic into a single entity known as an object while simultaneously concealing from the end user each of the implementation specifics of a class. It prohibits illegal access to the data as well as restricts the user to only using the data that is necessary for their tasks. The act of sending data that has been enhanced with many layers of control information before its transmission via a network is referred to as "data encapsulation." At the receiving end of a network, the successive layers of data are de-capsulated, which means they are removed (basically unwrapped). This process is the inverse of data encapsulation, which refers to the process of wrapping data in a container.

33. What is "association"?

A relationship is said to be an association when there is no owner, and each item in the association has its lifecycle. Take the case of the teacher and the student, for example. There isn't any ownership between the objects, and each student and instructor has their lifetime. While it is possible for several students to associate with a single teacher and for a single student to interact with multiple teachers, both scenarios are still possible. One to one, one to many, many to one, and many to many are the possible configurations for these interactions.

34. What Is a "friend function"?

If a function prototype is declared outside of the scope of the class and is prefaced with the term "friend," then it is granted permission to access all of the class's secret and protected members. Friends are not considered to be member functions of the class even when the prototype of the friend function is included in the definition of the class. Moving on to the second part of the topic, Java does not have the "friend" term, but the idea of a friend function could be achieved in Java by selecting the right access specifiers for such a class as well as the members of the class.

35. What do you understand by "multithreading"?

Java's multithreading capability, also known as simply numerous threads, is widely regarded as one of the programming language's most essential characteristics. As its name suggests, this refers to the capability of a central processing unit (CPU) to execute numerous threads autonomously all at the same time while sharing the resources of such a process simultaneously. Its primary CPU function is to allow for the simultaneous execution of numerous threads to make the most efficient use of the available CPU time. This is a feature of Java that allows one to subdivide a certain program into two or more threads so that the execution of the program can proceed in a manner that is both rapid and straightforward.

36. Can you explain “BlockingQueue''?

“BlockingQueue” mainly shows a queue that is thread-safe in its operation. The put() method is used by the producer thread to add resources or elements to the queue until the queue reaches its capacity, at which point the take() function is used by the consumer thread to remove items from the queue. However if a thread attempts to dequeue from such an empty queue, then perhaps a specific thread would be blocked until another thread inserts a product into the queue. Similarly, if a thread attempts to add an item into a queue that is already full, then just a specific thread would be blocked until other threads remove an item from the queue.

37. What is "numerical promotion"?

Converting a lower-precision numeric type into a higher-precision numeric type, often known as "numerical promotion," enables one to perform integer and floating-point operations just on higher-precision value. In the process of numerical promotion, values stored in bytes, characters, and shorts are converted to values stored in integers. In addition, the int values are changed to long values if that turns out to be necessary. When necessary, the long, as well as float values are changed to their corresponding double values.

38. Describe the process you would use to implement a thread pool.

The ThreadPool class is just a generic execution of such a thread pool. It accepts the following inputs: the size of the pool to be constructed as well as the name of a class which thus implements runnable (which must have a visible default function Object() { [native code] }). It then creates a thread pool with active threads that are waiting to also be activated. When the processing of the threads is complete, the threads return to the pool where they were waiting before.

39. What Is “Appletviewer''?

The majority of Java development environments come equipped with a specialized application that is referred to as an appletviewer. If you make use of the appletviewer, you will be able to put your applet into action in the same manner as if it were operating while being displayed on a web page via a browser. Because an appletviewer can run your applet more quickly than a browser in the majority of instances, using an appletviewer to test your applet is an extremely useful option. You will need to make sure that your applet is functioning properly at regular intervals so that you can add new features. You could test out your applet in a hurry with the help of the appletviewer rather than having to fire up the Java-enabled web browser.

40. What do you understand about "Superclass"?

Whenever you derive a class in Java from some other class, you can construct relationships between the different classes. It is common practice to refer to the parent class, also known as the class from which the class child is being derived, as either the superclass or perhaps the base class. A regular class is used as the basis for the superclass, after which it is extended by a third class. To put that another way, you don't have to make any specific changes to the class for it to be promoted to the status of the superclass. If someone else decides to build a new subclass that is derived from your class, all of the classes that you write have the potential to one day become a superclass.

41. What are "default constructors"?

Whenever you are creating your classes, you must always make sure to supply one or more function Object() { [native code] } methods. On the other hand, if you do not supply a function Object() { [native code] }, Java will provide one for you based on its default settings. After allocating enough disc memory to store the object, Java's default function Object() { [native code] } will next proceed to initialize all instance variables to their respective default values.

42. What is the difference between method overloading and method overriding?

The methods of a single class can override one another through a process known as overloading. Overriding methods utilize the same signature, which means they have the same name as well as method arguments as the original method. The names of methods that are overloaded are consistently the same, but their parameters are always different. The procedure that should be called is determined at the time of compilation when overloading is used.

43. What is it that a query optimizer does?

The query optimizer, which is also referred to as merely the optimizer, is a piece of built-in SQL database that finds the most effective way for a SQL statement to retrieve the data that has been requested. The query optimizer is considered an essential part of database management.

44. What is database replication?

The process of transferring data from such a central database between one or more additional databases is referred to as database replication. Since database replication distributes the data to users located at different sites, the central database is sometimes referred to as the publication database. The information contained in the publication database is replicated and made available in subscription databases located in various parts of the world. You can find database replication very interesting and useful. Database replication requires expertise to use optimally. 

Sample HR questions

Here are some of the frequently asked questions during the HR round in L&T interviews; you should prepare the answers for these questions to crack the interview.

45. Are you aware of the core Java concepts?

46. Can you tell me about at least 2 good projects you worked on?

47. What do you think about career development?

48. Can you walk me through your educational degrees and previous projects?

49. Do you believe that you have problem-solving skills?

50. Do you think that you have the required programming skills for this job?

51. Tell me something that is not mentioned in your resume and something about your current project?

52. What would you like to do to keep work pressure in check?

53. Will you be able to handle stressful situations?

54. Why do you want to be part of L&T?

55. Can you tell us the current project you are working on as well as previous projects?

56. Have you ever worked on user-level applications?

About L&T

L&T, which stands for Larsen & Toubro Limited, is just an Indian conglomerate that operates globally and is engaged in a variety of industries, including technology, engineering, architecture, manufacturing, as well as financial sectors. It is also generally referred to as L&T. The headquarters of the company may be found in Mumbai, which is located in Maharashtra, India. The corporation has business interests in a variety of fields, including construction, property investment, basic and heavy engineering, information technology, production of capital goods, and the provision of financial services.

By providing customers with numerous different avenues to pursue, the business makes its products and services more approachable. It is a worldwide, diversified company that operates in several services and product sectors, including technology, engineering, architecture, manufacturing, as well as financial services. Because of the magnitude of the company's achievements, it has developed a reputable brand. It is also considered among the top service providers in different industries.

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