20+ Sify Technologies Interview Questions and Answers

HashMap is non-synchronized and allows null values and keys, while HashTable is synchronized and does not allow null values or keys.

• HashMap is non-synchronized, meaning it is not thread-safe, while HashTable is synchronized and thread-safe.

• HashMap allows null values and keys, while HashTable does not allow null values or keys.

• HashMap is generally preferred for non-threaded applications, while HashTable is used in multi-threaded environments.

• Example: HashMap map = new HashMap<...read more

Controller method for validating user name and password

• Accept user input for username and password

• Check if username and password meet specified criteria (e.g. length, special characters)

• Query database to verify if username and password match stored credentials

• Return success or error message based on validation results

Streams in software development are sequences of data that can be processed sequentially or in parallel.

• Streams are used for processing large amounts of data efficiently.

• They can be used for reading from or writing to files, network connections, or other sources.

• Streams can be processed synchronously or asynchronously.

• Examples include reading a file line by line, processing a stream of sensor data, or downloading a large file in chunks.

Use Java 8 stream API to sort a list of integers

• Use stream() method to convert the list to a stream

• Use sorted() method to sort the integers

• Collect the sorted integers back to a list using collect() method

Java 8 stream is a sequence of elements that supports functional-style operations.

• Java 8 stream allows for processing collections of objects in a functional way.

• Streams can be created from various data sources like collections, arrays, or I/O resources.

• Common stream operations include map, filter, reduce, and collect.

• Streams are lazy, meaning they only perform operations when necessary.

• Example: List names = Arrays.asList("Alice", "Bob", "Charlie"); Stream stream = names.strea...read more

A clonable object is an object that can create a copy of itself, allowing for duplication without affecting the original object.

• Clonable objects implement the Cloneable interface in Java.

• The clone() method is used to create a copy of the object.

• Cloning can be shallow or deep, depending on the requirements.

• Examples of clonable objects include ArrayList, HashMap, and custom classes that implement Cloneable.

Java 8 introduced lambda expressions, functional interfaces, streams, and default methods in interfaces.

• Lambda expressions allow you to pass functionality as an argument to a method.

• Functional interfaces have a single abstract method and can be used with lambda expressions.

• Streams provide a way to work with sequences of elements efficiently.

• Default methods allow interfaces to have methods with implementation.