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Articles by Mahesh Parahar
Page 3 of 14
How to copy a list to another list in Java?
A List of elements can be copied to another List using multiple ways.Way #1Create a List by passing another list as a constructor argument.List copyOflist = new ArrayList(list);Create a List and use addAll() method to add all the elements of the source list.Way #2List copyOfList = new ArrayList(); copyOfList.addAll(list);Way #3Use Collections.copy() method to copy the contents of source list to destination. Existing elements will be overridden by indexes if any.Collections.copy(copyOfList, list);Way #4Use Streams to create a copy of a list.List copyOfList = list.stream().collect(Collectors.toList());ExampleFollowing is the example to explain the creation of copy of List object using multiple ways −package com.tutorialspoint; ...
Read MoreDifference between Paging and Segmentation
PagingPaging is a memory management technique in which process address space is broken into blocks of the same size called pages (size is power of 2, between 512 bytes and 8192 bytes). The size of the process is measured in the number of pages. Similarly, main memory is divided into small fixed-sized blocks of (physical) memory called frames and the size of a frame is kept the same as that of a page to have optimum utilization of the main memory and to avoid external fragmentation.Similarly, main memory is divided into small fixed-sized blocks of (physical) memory called frames and ...
Read MoreDifference between DNS and DHCP
A Domain Name System (DNS) server is used to translate domain names to IP Addresses and vice versa. DHCP is a client/server protocol that automatically assigns an IP address and other configuration information to an Internet Protocol (IP) host.Read through this article to find out more about DNS and DHCP and how they are different from each other.What is DNS?DNS is a hierarchical and decentralized naming system for computers, and other resources that are connected to a private network or the Internet. It connects a variety of bits of data to domain names assigned to each of the participants.DNS transforms ...
Read MoreHow do you create a list in Java?
A List of elements can be created using multiple ways.Way #1Create a List without specifying the type of elements it can holds. Compiler will throw warning message for it.List list = new ArrayList();Create a List and specify the type of elements it can holds.Way #2List list = new ArrayList();Way #3Create and initialize the list in one line.List list = Arrays.asList(object1, object 2);ExampleFollowing is the example to explain the creation of List objects −package com.tutorialspoint; import java.util.*; public class CollectionsDemo { public static void main(String[] args) { List list = new ArrayList(); list.add("Zara"); ...
Read MoreHow do you add two lists in Java?
We can use addAll() methods of List to add two lists.Use addAll() method without index parameterboolean addAll(Collection
Read MoreHow do I search a list in Java?
Streams can be used to search an item within list.Student student2 = list.stream().filter(s -> {return s.getRollNo() == rollNo);}).findAny().orElse(null);In this example, we're searching a student by roll number.ExampleFollowing is the example showing the usage of streams to search an item in a list −package com.tutorialspoint; import java.util.ArrayList; import java.util.List; public class CollectionsDemo { public static void main(String[] args) { List list = new ArrayList(); list.add(new Student(1, "Zara")); list.add(new Student(2, "Mahnaz")); list.add(new Student(3, "Ayan")); System.out.println("List: " + list); final int rollNoToSearch ...
Read MoreCan we convert a List to Set and back in Java?
A list can be converted to a set object using Set constructor. The resultant set will elliminate any duplicate entry present in the list and will contains only the unique values.Set set = new HashSet(list);On similar pattern, we can get a list from a set using its constructor.List list = new ArrayList(set);ExampleFollowing is the example showing the conversion of list to set and set to list −package com.tutorialspoint; import java.util.ArrayList; import java.util.Arrays; import java.util.HashSet; import java.util.List; import java.util.Set; public class CollectionsDemo { public static void main(String[] args) { List list = new ArrayList(Arrays.asList(1, 2, ...
Read MoreCan we convert an array to list and back in Java?
The List provides two methods to convert a List into Array.1. Use toArray() method without parameter.Object[] toArray()ReturnsAn array containing all of the elements in this list in proper sequence.2. Use toArray() with array. T[] toArray(T[] a)Type ParameterT − The runtime type of the array.Parametersa − The array into which the elements of this list are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.ReturnsAn array containing the elements of this list.ThrowsArrayStoreException − If the runtime type of the specified array is not a supertype of the runtime type ...
Read MoreHow to convert a Java list to a set?
A list can be converted to a set object using Set constructor. The resultant set will elliminate any duplicate entry present in the list and will contains only the unique values.Set set = new HashSet(list);Or we can use set.addAll() method to add all the elements of the list to the set.set.addAll(list);Using streams as well, we can get a set from a list.set = list.stream().collect(Collectors.toSet());ExampleFollowing is the example showing the list to set conversion via multiple ways −package com.tutorialspoint; import java.util.ArrayList; import java.util.Arrays; import java.util.HashSet; import java.util.List; import java.util.Set; import java.util.stream.Collectors; public class CollectionsDemo { public static void ...
Read MoreHow to check the Java list size?
List provides a method size() to check the current size of the list.Syntaxint size()Returns the number of elements in this list. If this list contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.ReturnsThe number of elements in this list.ExampleThe following example shows how to get size of a list using size() method.package com.tutorialspoint; import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class CollectionsDemo { public static void main(String[] args) { List list = new ArrayList(Arrays.asList(1, 2, 3, 4)); System.out.println("List: " + list); System.out.println("List Size: " + list.size()); list.add(5); ...
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