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1. Collections in java interview questions how to#
2. Collections in java interview questions full#
3. Collections in java interview questions software#
4. Collections in java interview questions code#

You can reverse an ArrayList using the reverse() function of the Collections class. You can convert an ArrayList into an Array using the toArray() function of the ArrayList class, like so: You can convert an Array into an ArrayList by using the Array class’s asList() function. Is it possible to convert an ArrayList to Array and an Array to ArrayList? However, when you use the Collections.sort(Comparator) method, it will sort the elements according to the compare() method of the Comparator interface.ĩ. If you use the Collections.sort() method, it will sort the elements based on the natural order specified in the compareTo() method. In the Collections framework, sorting is usually implemented by using the Comparable and Comparator interfaces. It allows for easy management of a Java application. As a result, the Properties file is mainly used for storing information that is liable to change (for example, username and passwords. Yes, using the Properties file in Java extends a major advantage – if you change the values in this file, it will be automatically reflected, without requiring to recompile the Java class. Is it beneficial to use the Properties file? While the initial implementation of the equals() method checks if two objects are similar, it is necessary to override the equals() method if you wish to compare the objects based on their properties.Ħ. When should you override the equals() method in Java?

Collections in java interview questions how to#

Thus, elements in the queue interface are removed from the front and added from the rear end.Īlso Read: How to Code, Compile and Run Java Projectsĥ. Queue interface – This interface arranges the element in the First In First Out (FIFO) approach.

Collections in java interview questions full#

A map cannot have duplicate keys/elements.Ĭheck out upGrad’s Full Stack Development Bootcamp (JS/MERN) While the key is a unique hashcode, the value denotes the element. Map interface – It is a two-dimensional data structure that stores data in key-value pairs. Set models the mathematical set abstraction and is implemented by classes like HashSet, TreeSet, LinkedHashSet, etc. Unlike List, it does not support index-based search and does not define any order for the elements. Set interface – It is a collection class that cannot contain duplicate elements. It is implemented by using different classes like ArrayList, LinkedList, etc. So, you can access any element from its index. This interface supports the index-based search. List interface – It is an extended array containing ordered elements, along with their duplicates. Most collections in Java are inherited from the Collections interface.

Here are the five core interfaces in the Collections framework:Ĭollection interface – It is the foundation of the Java Collection hierarchy. Name the interfaces of the Collections framework. Master of Science in Computer Science from LJMU & IIITBĬaltech CTME Cybersecurity Certificate ProgramĮxecutive PG Program in Full Stack DevelopmentĤ.

Collections in java interview questions software#

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Collections in java interview questions code#

Moreover, since Generics eliminates the need to use casting and instanceof function, it makes the code clean and precise. Thus, by showing an error during the compilation, it helps prevent ClassCastException at runtime. If you try to add an element of a different type, Generics will display a compile-time error. Generics lets you specify or define the type of objects that a collection can store. What is the role of Generics in the Collections framework? While arrays do not offer ready-to-use methods (searching, sorting, insertion, etc.) for user requirements, collections always include ready-to-use methods.ģ.An array can only store homogeneous (similar or same) objects, whereas a collection can store a heterogeneous group of objects.However, you can alter a collection’s size according to your scaling needs.

It facilitates code reusability and interoperability. Here are a few benefits of the Java Collections framework: Also, it comes equipped with blocking interfaces along with their implementations in Java concurrent packages. Java Collections includes both Generics and Concurrent collection classes for thread-safe operations. What is the advantage of using the Collections framework? Java Collections Interview Questions & Answersġ.