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Articles on Trending Technologies
Technical articles with clear explanations and examples
The toArray(T[] a) method of CopyOnWriteArrayList in Java
The difference between toArray() and toArray(T[] arr) of the CopyOnWriteArrayList class is that both the methods returns an array containing all of the elements in this collection, but the latter has some additional features i.e. the runtime type of the returned array is that of the specified array.The syntax is as followspublic T[] toArray(T[] arr)Here, the parameter arr is the array into which the elements of the list are to be stored.To work with CopyOnWriteArrayList class, you need to import the following packageimport java.util.concurrent.CopyOnWriteArrayList;The following is an example to implement CopyOnWriteArrayList class toArray() method in JavaExampleimport java.util.Arrays; import java.util.concurrent.CopyOnWriteArrayList; ...
Read MoreCan we declare an abstract method, private, protected, public or default in java?
A method which does not have body is known as abstract method. It contains only method signature with a semi colon and, an abstract keyword before it.public abstract myMethod();To use an abstract method, you need to inherit it by extending its class and provide implementation to it.Declaring an abstract method privateIf a method of a class is private, you cannot access it outside the current class, not even from the child classes of it.But, incase of an abstract method, you cannot use it from the same class, you need to override it from subclass and use.Therefore, the abstract method cannot ...
Read MoreComparison of Exception Handling in C++ and Java
The exception handling feature is present almost any object oriented languages nowadays. In C++ and Java also we can get this kind of feature. There are some similarities between exception handling in C++ and exception handling in Java, like in both languages we have to use the try-catch block. Though there are some difficulties also. These are like below −In C++, we can throw any type of data as exception. Any type of data means primitive datatypes and pointers also. In Java we can only throw the throwable objects. Subclasses of any throwable class will also be throwable.Example#include using ...
Read MoreThe indexOf() method of CopyOnWriteArrayList class in Java
The indexOf() method of the CopyOnWriteArrayList class is used to get the index of the first occurrence of an element. The method has two two forms. Let us see them one by oneindexOf(Object o) methodThe indexOf(Object o) is used to get the index of the first occurrence of an element.The syntax is as followsindexOf(Object o)Here, o is the element for which you want the index. To work with CopyOnWriteArrayList class, you need to import the following packageimport java.util.concurrent.CopyOnWriteArrayList;The following is an example to implement CopyOnWriteArrayList class indexOf() method in JavaExampleimport java.util.concurrent.CopyOnWriteArrayList; public class Demo { public static void main(String[] ...
Read MoreCan we declare a top level class as protected or private in Java?
No, we cannot declare a top-level class as private or protected. It can be either public or default (no modifier). If it does not have a modifier, it is supposed to have a default access.Syntax// A top level class public class TopLevelClassTest { // Class body }If a top-level class is declared as private the compiler will complain that the modifier private is not allowed here. This means that a top-level class cannot be a private, the same can be applied to protected access specifier also.Protected means that the member can be accessed by any class in the same ...
Read MoreCan we have variables and methods in an enum in Java?
Enumeration (enum) in Java is a datatype which stores a set of constant values. You can use enumerations to store fixed values such as days in a week, months in a year etc.You can define an enumeration using the keyword enum followed by the name of the enumeration as −enum Days { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }Methods and variables in an enumerationEnumerations are similar to classes and, you can have variables, methods, and constructors within them. Only concrete methods are allowed in an enumeration.ExampleIn the following example, we are defining an enumeration with name ...
Read MoreGet SubList from LinkedList in Java
The subList of a LinkedList can be obtained using the java.util.LinkedList.subList(). This method takes two parameters i.e. the start index for the sub-list(inclusive) and the end index for the sub-list(exclusive) from the required LinkedList. If the start index and the end index are the same, then an empty sub-list is returned.A program that demonstrates this is given as follows −Exampleimport java.util.LinkedList; import java.util.List; public class Demo { public static void main(String[] args) { LinkedList l = new LinkedList(); l.add("John"); ...
Read MoreJava Program to strip a filename of its extension after the last dot
The method removeExtension() is used to strip a filename of its extension after the last dot. This method requires a single parameter i.e. the file name and it returns the file name without its extension.A program that demonstrates this is given as follows −Exampleimport java.io.File; public class Demo { public static String removeExtension(String fname) { int pos = fname.lastIndexOf('.'); if(pos > -1) return fname.substring(0, pos); else return fname; } public static void main(String[] args) { System.out.println(removeExtension("c:\JavaProgram\demo1.txt")); ...
Read MoreArrayBlockingQueue size() Method in Java
To get the number of elements in the queue, use the size() method of the ArrayBlockingQueue class.The syntax is as followsint size()To work with ArrayBlockingQueue class, you need to import the following packageimport java.util.concurrent.ArrayBlockingQueue;The following is an example to implement size() method of Java ArrayBlockingQueue classExampleimport java.util.concurrent.ArrayBlockingQueue; public class Demo { public static void main(String[] args) throws InterruptedException { ArrayBlockingQueue q = new ArrayBlockingQueue(10); q.add(200); q.add(310); q.add(400); ...
Read MoreThe remove() method of AbstractList class in Java
Remove an element at a specified position from the list using the remove() method. The position is to be set as index parameter in the method itself. It returns the element which is removed.The syntax is as follows:public E remove(int index)Here, index is the index from where you want to delete the element.To work with the AbstractList class, import the following package:import java.util.AbstractList;The following is an example to implement remove() method of the AbstractlList class in Java:Exampleimport java.util.ArrayList; import java.util.AbstractList; public class Demo { public static void main(String[] args) { AbstractList myList = new ArrayList(); ...
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