600+ APTRON Solutions Interview Questions and Answers

The game is not fair.

• Player X has a higher chance of winning as they only need to get a consecutive HEAD, TAIL.

• Player Y needs to get a consecutive HEAD, HEAD which is less likely to occur.

• The probability of Player X winning is higher than Player Y winning.

The last ball that will be left is black.

• When you take out 2 black balls, you take another white ball.

• If you take 2 white balls, you take out 1 black ball.

• If balls are of different color, you take out another black ball.

• Since there are more black balls initially, the last ball will be black.

Design a website similar to bookmyshow.com for booking cinema tickets for a single location with multiple theatres.

• Design a user-friendly GUI with options for advance booking, user login, user registration, movie rating, and saving card details.

• Create relevant database tables to store information about movies, theatres, bookings, user details, and card details.

• Link the GUI to the database to enable data flow and retrieval.

• Implement features like advance booking, where users c...read more

Program to remove duplicate elements from String and count their occurrences.

• Create a HashSet to store unique characters from the String.

• Iterate through the String and add each character to the HashSet.

• While adding, check if the character already exists in the HashSet and increment its count.

• Print the count of each character that has duplicates.

• Return the modified String with duplicates removed.

My phone uses iOS. Other phone operating systems available in the market are Android, Windows, and Blackberry OS.

• iOS is developed by Apple and is exclusive to iPhones and iPads.

• Android is developed by Google and is used by various phone manufacturers such as Samsung, LG, and HTC.

• Windows is developed by Microsoft and is used by Nokia and other phone manufacturers.

• Blackberry OS is developed by Blackberry and is exclusive to Blackberry phones.

The program prints the substring after a specified character has occurred a certain number of times in a given string.

• Iterate through the string to find the specified character.

• Keep track of the count of occurrences of the character.

• Once the count reaches the specified count, extract the substring after that position.

• Handle corner cases such as when the character is not in the string or when it doesn't occur the specified number of times.

To efficiently manage room bookings and prebookings in a hotel, a priority queue data structure can be implemented.

• A priority queue can be used to prioritize room bookings based on check-in dates.

• When a customer checks out, the room becomes available and can be assigned to the next customer in the priority queue.

• Prebookings can be stored separately and checked against the availability of rooms before assigning them to customers.

• The priority queue can be implemented using a bi...read more

Minimum number of times to turn all glasses upside down when 4 can be turned at a time.

• Turn over any four glasses, leaving one untouched.

• Repeat the above step until only one glass is left upside down.

• Finally, turn over the last glass to complete the task.

• Minimum number of turns required is 3.

Minimum 7 races required to find the top 3 fastest horses.

• Divide the 25 horses into 5 groups of 5 horses each.

• Conduct a race among the horses in each group to determine the fastest horse in each group.

• Take the top 2 horses from each group and conduct a race among them to determine the fastest horse overall.

• The winner of this race is the fastest horse.

• Now, take the second-place horse from the final race and the second-place horse from each group race.

• Conduct a race among these...read more

Marker interface is an interface with no methods. It is used to mark a class for special treatment.

• Marker interface is used to provide metadata to the JVM.

• It is used to indicate that a class has some special behavior or characteristics.

• Example: Serializable interface in Java.

• Marker interfaces are used for reflection and serialization.

• They are also used in frameworks like Spring and Hibernate.

• Marker interfaces are also known as tagging interfaces.

• They are used to group classes...read more

The minimum number of races required to find the top 3 among 25 horses is 7.

• Divide the 25 horses into 5 groups of 5 horses each.

• Race the 5 groups, which will give us the top 3 horses from each group.

• Now we have 15 horses remaining.

• Race the top 3 horses from each group, which will give us the top 3 horses overall.

• This requires a total of 7 races.

Print all possible paths from start to end in a linear way, moving either one or two steps right.

• Use dynamic programming to solve the problem

• Create a 2D array to store the number of paths to each position

• Start from the end position and work backwards

• At each position, calculate the number of paths by summing the number of paths from the next two positions

• Print all the paths by backtracking from the start position

A program to capitalize the first letter of each word in a sentence.

• Split the sentence into words

• Loop through each word and capitalize the first letter

• Join the words back into a sentence

Interview questions for Test Engineer position covering topics like testing types, bug life cycle, constructors, locators, and priority/severity.

• White box testing is testing the internal structure of the application, black box testing is testing the functionality without knowledge of internal structure, and grey box testing is a combination of both.

• Bug life cycle includes stages like new, open, assigned, fixed, verified, and closed.

• Deferred means postponing the bug fix to a l...read more

Remove strings from an array whose length is less than 3.

• Loop through the array and check the length of each string.

• If the length is less than 3, remove that string from the array.

• Use a for loop or filter method to remove the strings.

• Example: ['cat', 'dog', 'bird', 'elephant'] -> ['cat', 'dog', 'bird', 'elephant']

• Example: ['a', 'to', 'the', 'in'] -> ['the', 'in']

Lists are used for small collections, linked lists for large or frequently modified collections.

• Use lists for small collections that don't require frequent modifications.

• Use linked lists for large collections or collections that require frequent modifications.

• Linked lists are better for inserting or deleting elements in the middle of the collection.

• Lists are better for accessing elements by index.

• Example: Use a list to store a small list of names, use a linked list to impleme...read more

Answering questions related to 3-tier architecture, load balancer alternatives, PV and PVC creation in Kubernetes, cloud and networking, on-prem vs cloud, and server migration tools.

• To create a 3-tier architecture, separate the presentation layer, application layer, and database layer into three distinct tiers.

• Alternatives to Load Balancer include DNS-based load balancing and IP-based load balancing.

• To create PV and PVC in Kubernetes, use the kubectl command-line tool or YAML...read more

Modified Balanced Parentheses where characters can be matched with any other character.

• Use a stack to keep track of opening characters

• When encountering a closing character, check if it matches the top of the stack

• If it matches, pop from the stack, else return false

• Continue until end of string, return true if stack is empty

Interview questions for Software Developer related to Spring, Collections, Serialization, Exceptions, Unix, Annotations, Json, Build tools, Restful services, and more.

• List and Set are both collection interfaces in Java. List allows duplicates and maintains insertion order while Set doesn't allow duplicates and doesn't maintain any order.

• Sorted in Hashed Set means that the elements are stored in a sorted order based on their hash code.

• Serialization is the process of converting...read more

Abstract classes in Java are classes that cannot be instantiated and are used as blueprints for other classes.

• Abstract classes cannot be instantiated, meaning you cannot create objects of an abstract class.

• Abstract classes can have both abstract and non-abstract methods.

• Interfaces in Java are similar to abstract classes, but they cannot have any method implementations.

• A class can implement multiple interfaces, but it can only extend one abstract class.

• Abstract classes can hav...read more

Microcontroller is a self-contained system with memory, peripherals and processor, while microprocessor only has a processor.

• Microcontroller has on-chip memory and peripherals, while microprocessor requires external memory and peripherals.

• Microcontroller is used in embedded systems, while microprocessor is used in general-purpose computing.

• Examples of microcontrollers include Arduino, PIC, and AVR, while examples of microprocessors include Intel Pentium, AMD Ryzen, and ARM Co...read more

Print all possible combinations of strings by picking one character from each string in the array.

• Iterate through each character of the first string and combine it with each character of the second string.

• Repeat the process for all strings in the array to get all possible combinations.

• Use nested loops to generate combinations efficiently.

The code inserts two numbers in a text file, ensuring that the second number is greater than the first and there is no overlap between entries.

• Read the existing entries from the text file

• Check if the new numbers satisfy the conditions

• If conditions are met, insert the new numbers into the file

• Otherwise, display an error message

Program to separate even and odd numbers using Java 8.

• Use Java 8 Stream API to filter even and odd numbers

• Create two separate lists for even and odd numbers

• Use lambda expressions to filter the numbers

• Example: List evenNumbers = numbers.stream().filter(n -> n % 2 == 0).collect(Collectors.toList());

• Example: List oddNumbers = numbers.stream().filter(n -> n % 2 != 0).collect(Collectors.toList());

Sensitive information can be removed from serializable interface by implementing custom serialization.

• Create a custom serialization method that excludes sensitive information.

• Use the transient keyword to mark sensitive fields as non-serializable.

• Consider using encryption or hashing to protect sensitive data.

• Test serialization and deserialization to ensure sensitive information is not included.

• Examples: exclude passwords, credit card numbers, and personal identification inform...read more

Yes, an array can have elements of different data types.

• An array can have elements of different data types, but it's not recommended.

• It can make the code harder to read and maintain.

• For example, an array can have both strings and numbers: ['apple', 5, 'banana']

Interview questions for Application Engineer role covering various topics.

• Subset sum variant - finding a subset of numbers that add up to a given sum

• Single loop missing number - finding a missing number in an array using a single loop

• Difference between two dates - calculating the difference between two dates in Java

• Core Java concepts - knowledge of basic Java concepts such as inheritance, polymorphism, etc.

• SQL - knowledge of SQL queries and database management

• Finding duplicat...read more

I recently downloaded VLC media player.

• Visited the official website of VLC media player

• Clicked on the download button

• Selected the appropriate version for my operating system

• Waited for the download to complete

• Opened the downloaded file and followed the installation wizard

Overloading is when multiple methods have the same name but different parameters. Overriding is when a subclass provides a different implementation of a method inherited from its superclass.

• Overloading allows a class to have multiple methods with the same name but different parameters.

• Overriding occurs when a subclass provides a different implementation of a method inherited from its superclass.

• Overloading is resolved at compile-time based on the method signature.

• Overriding i...read more

Java program to calculate date n days after given date without using Date parsing libraries.

• Parse the input date string to extract day, month, and year components.

• Calculate the total number of days represented by the input date.

• Add the specified number of days to the total days calculated.

• Convert the final total days back to day, month, and year components to get the new date.

Density of a person in a social networking graph is the ratio of friends who interacted with the person to the total number of friends.

• Calculate the number of friends who interacted with the person.

• Calculate the total number of friends for that person.

• Divide the number of interacting friends by the total number of friends to get the density.

• Density = (Number of interacting friends) / (Total number of friends)

Undo operation (ctrl + z) is implemented by maintaining a stack of previous states.

• When a change is made, the current state is pushed onto the stack

• When undo is called, the top state is popped and applied

• Redo is implemented by maintaining a stack of undone states

• Some applications may also implement a limit on the number of undo/redo steps

• Undo/redo can be implemented at different levels (e.g. character, word, paragraph)

Java Map is an interface that maps unique keys to values. It works internally using hash table data structure.

• Map interface is implemented by HashMap, TreeMap, LinkedHashMap, etc.

• Keys in a map must be unique and values can be duplicated.

• Hash table data structure is used to store key-value pairs internally.

• Hashing is used to convert keys into indices of an array where values are stored.

• Collision resolution techniques like chaining and open addressing are used to handle collisi...read more