What are the interview questions on collections in Java?
Java Collections Interview Questions
- What are Collection related features in Java 8?
- What is Java Collections Framework?
- What is the benefit of Generics in Collections Framework?
- What are the basic interfaces of Java Collections Framework?
- Why Collection doesn’t extend Cloneable and Serializable interfaces?
Which of the following collection is ordered collections?
The List is an ordered collection which maintains the insertion order whereas Set is an unordered collection which does not preserve the insertion order. The List interface contains a single legacy class which is Vector class whereas Set interface does not have any legacy class.
What is front controller in struts?
Front Controller is StrutsPrepareAndExecuteFilter. It uses the concept of RequestProcessor class while processing request. It uses the concept of Interceptors while processing the request. It has only JSP for the view component.
What are the different collection views provided by the map interface?
The Map interface provides 3 views of key-value pairs which are: key set view. value set view. entry set view.
Is collection a class or interface?
In Java, collection is an interface. In Java, collections is a utility class.
What is difference between collections and collection?
Collection is the interface where you group objects into a single unit. Collections is a utility class that has some set of operations you perform on Collection. Collection does not have all static methods in it, but Collections consist of methods that are all static.
What is difference between collection and collections?
Which design pattern is used in Struts?
What design patterns are used in Struts? Struts is based on model 2 MVC (Model-View-Controller) architecture. Struts controller uses the command design pattern and the action classes use the adapter design pattern. The process() method of the RequestProcessor uses the template method design pattern.
What configuration files are used in Struts?
Configuration Files
| File | Optional | Purpose |
|---|---|---|
| struts.xml | yes | Main configuration, contains result/view types, action mappings, interceptors, and so forth \ |
| default.properties | yes | Framework properties |
| struts-default.xml | yes | Default configuration provided by Struts |
| struts-default.vm | yes | Default macros referenced by velocity.properties |
What is diff between collection and collections?
Need For Collections?
| Collection | Collections |
|---|---|
| The Collection is an interface that includes a static method since the launch of Java8. The Interface can contain default and abstract methods. | It contains static methods only. |
| It extends the iterable interface. | It extends the Object class. |
Why HashMap is not part of collection?
Because they are of an incompatible type. List, Set and Queue are a collection of similar kind of objects but just values where a Map is a collection of key and value pairs.
Is collections a utility class?
Collections class is one of the utility classes in Java Collections Framework. The java. util package contains the Collections class.
Why do we use collections?
Collections are used to store, retrieve, manipulate, and communicate aggregate data. Typically, they represent data items that form a natural group, such as a poker hand (a collection of cards), a mail folder (a collection of letters), or a telephone directory (a mapping of names to phone numbers).
Is collections a class or interface?
What are the features of Struts?
The important features of struts 2 framework are as follows:
- Configurable MVC components.
- POJO based actions.
- AJAX support.
- Integration support.
- Various Result Types.
- Various Tag support.
- Theme and Template support.
What is Struts 2 used for?
Apache Struts 2 is an open-source web application framework for developing Java EE web applications. It uses and extends the Java Servlet API to encourage developers to adopt a model–view–controller (MVC) architecture.
What is the purpose of struts xml?
The struts-config. xml configuration file is a link between the View and Model components in the Web Client. It plays an important role in building both Controller components and Application-specific configurations. In Web NMS, this file is created specific to every application in the format as <module>-struts-config.
Where is struts xml?
The core configuration file for the framework is the default ( struts. xml ) file and should reside on the classpath of the webapp (generally /WEB-INF/classes ). The default file may include other configuration files as needed.
What are the methods of collections?
Collections Class in Java
| Methods | Description |
|---|---|
| emptySortedMap() | This method returns an empty sorted map (immutable). |
| emptySortedSet() | This method returns an empty sorted set (immutable). |
| enumeration(Collection<T> c) | This method returns an enumeration over the specified collection. |
Is collection an interface or class?
What are collections types of collections?
Java Collection framework provides many interfaces (Set, List, Queue, Deque) and classes (ArrayList, Vector, LinkedList, PriorityQueue, HashSet, LinkedHashSet, TreeSet).
…
Methods of Collection interface.
| No. | Method | Description |
|---|---|---|
| 19 | public int hashCode() | It returns the hash code number of the collection. |
How many interfaces are in a collection?
The collection hierarchy consists of six interfaces, the core collection intefaces. Three of these interfaces, Set, List, and SortedSet are descendants of the Collection interface; they add further constraints on the contracts imposed by the methods in this interface, as well as adding new methods.
What are the applications of Struts?
Struts is an open source framework that extends the Java Servlet API and employs a Model, View, Controller (MVC) architecture. It enables you to create maintainable, extensible, and flexible web applications based on standard technologies, such as JSP pages, JavaBeans, resource bundles, and XML.
What are the advantages of Struts?
Advantages of Struts. Since Struts follow MVC framework, Java, JSP and Action classes are highly maintained and easy to understand for developers. The development time is less and this creates an advantage for the application developers. It is easy to maintain the applications due to the MVC framework.
What is the latest version of Struts?
Struts 2.5. 22 is the most current version of the Struts 2 framework and was released on November 29, 2019. The Struts 2.5.