Yubi Java Developer Interview Questions and Answers

Static is a keyword in Java used to create class-level variables and methods.

• Static variables are shared among all instances of a class

• Static methods can be called without creating an instance of the class

• Static blocks are used to initialize static variables

• Static import is used to import static members of a class

The program replaces consecutive same characters in a string with a single '$'.

• Iterate through each character in the string

• Compare the current character with the next character

• If they are the same, replace the next character with '$'

• Continue until the end of the string

Function overloading is having multiple functions with the same name but different parameters. Function overriding is having a derived class implement a method with the same name and parameters as a method in its base class.

• Function overloading is used to provide different ways of calling a function with different parameters.

• Function overriding is used to provide a specific implementation of a method in a derived class...read more

Exceptions are errors that occur during program execution and can be handled using try-catch blocks.

• Checked exceptions: must be handled or declared in the method signature

• Unchecked exceptions: occur at runtime and do not need to be declared

• Error: serious problems that cannot be handled, such as OutOfMemoryError

• Examples: NullPointerException, ArrayIndexOutOfBoundsException

Exceptions should be handled gracefully to prevent application crashes.

• Use try-catch blocks to catch exceptions.

• Handle exceptions at the appropriate level of abstraction.

• Log exceptions to aid in debugging.

• Provide meaningful error messages to the user.

• Avoid catching generic exceptions.

• Use finally blocks to release resources.

• Consider using custom exceptions for specific error conditions.

To create a custom read-only list, use the ReadOnlyCollection class in C#.

• Create a List object with the desired elements.

• Use the AsReadOnly() method to create a read-only wrapper around the list.

• Use the ReadOnlyCollection class to create a truly read-only list.

• Example: List myList = new List{"apple", "banana", "orange"};

• Example: var readOnlyList = myList.AsReadOnly();

• Example: var trulyReadOnlyList = new ReadOnlyCollect

Collections are data structures that store and manipulate groups of related objects.

• Collections are used to store and manipulate groups of related objects

• They can be classified into three main categories: Lists, Sets, and Maps

• Lists maintain the order of elements and allow duplicates (e.g. ArrayList, LinkedList)

• Sets do not allow duplicates and do not maintain order (e.g. HashSet, TreeSet)

• Maps store key-value pairs and d...read more

Binary search is a search algorithm that finds the position of a target value within a sorted array.

• The array must be sorted before applying binary search

• Compare the target value with the middle element of the array

• If the target value is smaller, search the left half of the array

• If the target value is larger, search the right half of the array

• Repeat until the target value is found or the search space is exhausted