Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Object Oriented Programming Articles
Page 486 of 589
What is the use of the Tab key in JShell in Java 9?
JShell can also provide an auto-completion feature when we partially type the name of an existing class, variable, or method by pressing the Tab key. If an item can't determine from what we entered, then possible options are provided.Pressing the Tab key in JShell performs one of the following tasks:If no other name matches what we have typed, JShell enters the rest of the name for us.If there are multiple names that begin with the same letters, then JShell displays a list of those names to help what to type next, then type the next letter(s) and press tab key ...
Read MoreHow can we create an unmodifiable List in Java 9?
A list considered to be unmodifiable if the elements can't be added, removed, or replaced from a list once an unmodifiable instance of a list has created. The static factory method: List.of() provides a convenient way to create unmodifiable lists in Java 9.An instance of a list created by using the List.of() method has the following characteristics.The list returned by a factory method is conventionally immutable. It means that the elements can't be added, removed, or replaced from a list. Calling any mutator method on the List causes UnsupportedOperationException.If the contained elements of List are mutable, it may cause the ...
Read MoreImportance of iterate() method of Stream API in Java 9?
In Java 8, the iterate() method of Stream API takes the seed and the unary operator as arguments. As stream becomes infinite, it makes the developer add explicit termination conditions by using limit, findFirst, findAny and etc. In Java 9, the iterate() method of Stream API has added a new argument, a predicate that takes the condition to break the flow.Syntaxstatic Stream iterate(T seed, Predicate
Read MoreWhat does the method removeRange(int fromIndex, int toIndex) do in java?
The removeRange() method of the ArrayList class removes all of the elements from this List whose index is between fromIndex and toIndex.Exampleimport java.util.*; public class ArrayListDemo extends ArrayList{ public static void main(String[] args) { ArrayListDemo arrlist = new ArrayListDemo(); arrlist.add(10); arrlist.add(12); arrlist.add(31); System.out.println("The list:" + arrlist); arrlist.removeRange(0,2); System.out.println("The list after using removeRange:" + arrlist); } }OutputThe list:[10, 12, 31] The list after using removeRange:[31]
Read MoreWhat does the method set(int, obj o) do in java?
The set() method of the ArrayList class replaces the element at the specified position in this list with the specified element.Exampleimport java.util.ArrayList; public class Sample { public static void main(String args[]) { ArrayList al = new ArrayList(); System.out.println("Initial size of al: " + al.size()); al.add("C"); al.add("A"); al.add("E"); al.add(1, "A2"); System.out.println("Size of al after additions: " + al.size()); System.out.println("Contents of al: " + al); System.out.println("Size of al after deletions: " + al.size()); ...
Read MoreWhat does the method indexOf(obj o) do in java?
The indexOf(Object) method of the java.util.ArrayList class returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.Exampleimport java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { ArrayList arrlist = new ArrayList(5); arrlist.add("G"); arrlist.add("E"); arrlist.add("F"); arrlist.add("M"); System.out.println("Size of list: " + arrlist.size()); for (String value : arrlist) { System.out.println("Value = " + value); } ...
Read MoreWhat does the method size() do in java?
The size() method of the class java.util.ArrayList returns the number of elements in this list i.e. the size of the list.Exampleimport java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { ArrayList arrlist = new ArrayList(5); arrlist.add(15); arrlist.add(20); arrlist.add(25); arrlist.add(22); for (Integer number : arrlist) { System.out.println("Number = " + number); } int retval = arrlist.size(); System.out.println("Size of list = " + retval); } }OutputNumber = 15 Number = 20 Number = 25 Number = 22 Size of list = 4
Read MoreWhat does the method remove(obj o) do in java?
The remove(Object) method of the class java.util.ArrayList removes the first occurrence of the specified element from this list, if it is present. If the list does not contain the element, it is unchanged.Exampleimport java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { ArrayList arrlist = new ArrayList(5); arrlist.add("G"); arrlist.add("E"); arrlist.add("F"); arrlist.add("M"); arrlist.add("E"); System.out.println("Size of list: " + arrlist.size()); for (String value : arrlist) { System.out.println("Value = " + ...
Read MoreHow to truncate a file in Java?
The flush() method of the FileWriter class flushes the contents of the file. You can use this method to truncate a file.Exampleimport java.io.File; import java.io.FileWriter; public class FileTruncate { public static void main(String args[]) throws Exception { File file = new File("myData"); FileWriter fw = new FileWriter(file, false); fw.flush(); System.out.println("File truncated"); } }OutputFile truncated
Read MoreHow to capture file not found exception in Java?
While using FileInputStream, FileOutputStream, and RandomAccessFile classes, we need to pass the path of the file to their constructors. In case of a file in the specified path does not exist a FileNotFoundException is raised.Examplepublic class Sample { public static void main(String args[]) throws Exception { File file = new File("myFile"); FileInputStream fis = new FileInputStream(file); System.out.println("Hello"); } }OutputException in thread "main" java.io.FileNotFoundException: myFile (The system cannot find the file specified) ...
Read More