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InputStream and OutputStream both are the abstraction process which can be implemented to access the low level data sets as pointers . They are the signified APIs to specify a particular data sequence of an operation by following some individual steps. The InputStream rearranges a data set as an ordered stream of bytes which actually reads the data from a file or received by using a network system. After ending the stream process it will return -1 as an integer value as Java does not contain any unsigned byte as data type. An OutputStream is a streamed process which mainly ... Read More
Inheritance is a Method to create a hierarchy between multiple classes by replicating some properties from others. There are various types of inheritance present in Java, such as single inheritance, multiple inheritance, multilevel inheritance, hybrid inheritance, and hierarchical inheritance. Interface is the blueprint of a particular class which consists of the constant and abstract class. The interface class allows a machine to apply some specific properties on an object or a class. It is totally an abstract method which helps to perform the Java abstraction on a collection by specifying the behavior of a class. Now the task ... Read More
LinkedHashMap is a class that is identical to HashMap, however it additionally provides a feature that tracks the order wherein components are inserted. The sequence wherein elements were added isn't preserved by using HashMap, even though it does permit for quick element insertion, search, and deletion. By keeping a linked list of every entry in the map, LinkedHashMap addresses this issue. The elements are saved in the sequence that they were introduced thanks to this linked list. As a result, while iterating over a LinkedHashMap, the elements are returned according to how they were added. Methods Used To iterate LinkedHashMap ... Read More
The HashTable is a fundamental data structure that operates on the basis of key hashcodes without preserving the insertion order. It prohibits duplicate keys but allows for duplicate values. Remarkably, it accommodates a wide range of objects for both keys and values, fostering heterogeneity. Null values for keys and values are not allowed, though, as doing so would cause a RunTimeException called a NullPointerException. The HashTable implements the serializable and cloneable interfaces in terms of interfaces, but it fails to implement the RandomAccess interface. Additionally, all the methods within the HashTable are synchronized, ensuring thread safety for HashTable objects. When ... Read More
The LinkedHashMap Class is similar to HashMap. But it has an additional feature in comparison to HashMap. The LinkedList class belongs to the java.util package. A doubly linked list is how LinkedList stores its elements. Given that our operations typically include insertion and deletion, LinkedList is the best option. The java.util package contains the LinkedList collection framework. It acts as an implementation of the non-contiguous LinkedList data structure, which saves elements in memory. Methods Used There are five main methods that you can use for iterating HashMap − Using the for loop Making use of a while loop Using ... Read More
The priority Queue is the abstract data type which is similar to the queue or stack, in which each element is attached with a priority. Here the priority determines the order of the elements to be dequeued from the queue and the higher priority elements are dequeued before the elements with the lower priority. The priority queues will be implemented using different data structures such as heaps, arrays or balanced trees. The most commonly used implementation is the heap, which is the binary tree based data structure having the value of each node greater than or equal to the values ... Read More
The Vector class has been a part of the Java collection system since Java version 1.2. Vectors are sometimes known as Dynamic Arrays because, unlike ordinary arrays, they can expand and contract in size. Ensuring thread-safety, Vectors are synchronized. While there exists a third approach that involves using Apache Commons to iterate through the vector in reverse, this method necessitates the downloading of additional jar files and packages, which is not widely supported by most systems. Essentially, there are only two primary methods to traverse through vector elements in reverse order. Methods Used There are two methods used here − ... Read More
The Reflection API in Java allows you to dynamically call any method using its string name. When using the java.lang.reflect API, you can load classes by name even if they aren't accessible at compile time thanks to reflection's robust mechanism. It empowers you to dynamically invoke any method using reflection and makes it possible you to retrieve all methods from a class, including private and public ones. Those who are unfamiliar with Java might find this idea strange. With no explicit code for calling the method during compilation, Java can execute a method when its name is provided as a ... Read More
(Key, Value) pairs are used to store data in Java HashMap collections. Although it is unsynchronized, it is comparable to HashTable. As a result, a HashMap can be accessed by numerous threads without encountering any troubles. Despite the fact that HashMap allows for the storage of null keys as well, there can most effective be one null key object and an infinite wide variety of null values. regarding the order of the map, this class gives no guarantees. To index the value, the key is utilised. We can store unique keys with HashMap. If we try to insert one, the ... Read More
A data structure known as a 2D list or list of lists can be utilised for saving a collection of data in a two-dimensional format. A row in the 2D list is represented by each inner list in this list of lists. A 2D list could be utilised, for instance, to store the data for a chessboard, where every component in the list corresponds to a single square on the board. Methods Used A 2D list can be iterated in one of the two methods that follow − Using Loops Using iterator Method 1: Employing Loops There are ... Read More