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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to convert Wrapper value array list into primitive array in Java?
Here, to convert Wrapper value array list into primitive array, we are considering Integer as Wrapper, whereas double as primitive.At first, declare an Integer array list and add elements to it −ArrayList < Integer > arrList = new ArrayList < Integer > (); arrList.add(5); arrList.add(10); arrList.add(15); arrList.add(20); arrList.add(25); arrList.add(30); arrList.add(45); arrList.add(50);Now, convert the above Integer array list to primitive array. Firstly, we set the same size for the double array and then assigned each valuefinal double[] arr = new double[arrList.size()]; int index = 0; for (final Integer value: arrList) { arr[index++] = value; }The following is an example to ...
Read MoreReplace all the elements of a Vector with Collections.fill() in Java
All the elements of a vector can be replaced by a specific element using java.util.Collections.fill() method. This method requires two parameters i.e. the Vector and the element that replaces all the elements in the Vector. No value is returned by the Collections.fill() method.A program that demonstrates this is given as follows:Exampleimport java.util.Collections; import java.util.Vector; public class Demo { public static void main(String args[]) { Vector vec = new Vector(5); vec.add(7); vec.add(4); vec.add(1); ...
Read MoreIntStream boxed() method in Java
The boxed() method of the IntStream class returns a Stream consisting of the elements of this stream, each boxed to an Integer.The syntax is as follows.Stream boxed()At first, create an IntStreamIntStream intStream = IntStream.range(20, 30);Now, use the boxed() method to return a Stream consisting of the elements of this stream, each boxed to an Integer.Stream s = intStream.boxed();The following is an example to implement IntStream boxed() method in Java.Exampleimport java.util.*; import java.util.stream.Stream; import java.util.stream.IntStream; public class Demo { public static void main(String[] args) { IntStream intStream = IntStream.range(20, 30); Stream s = intStream.boxed(); ...
Read MoreJava Program to output fixed number of array elements in a line
To output fixed number of array elements in a line, we should check for a condition and if that is true, we should place System.out.println(); properly to get a line and the process goes on.Here, we will display 5 elements in a line. At first, create a new integer array and add some elements −int[] list = new int[50]; for (int i = 0; i < list.length; i++) { list[i] = (int)(i + 20); }Now, declare a new variable and initialize it to 0. This variable is checked in a for loop that loops until the length of the ...
Read MoreWhile working with Java in eclipse I got a warning saying "dead code". What does it mean?
A code block/statement in Java to which the control never reaches and never gets executed during the lifetime of the program is known as unreachable block/statement.public class UnreachableCodeExample { public String greet() { System.out.println("This is a greet method "); return "Hello"; System.out.println("This is an unreachable code "); } public static void main(String args[]) { new UnreachableCodeExample().greet(); } }Dead codeA dead code is an unreachable code, but it doesn’t generate compile time error. But if you execute it in eclipse it gives you a warning.ExampleIn ...
Read MoreCreate a new ArrayList from another collection in Java
An ArrayList can be created from another collection using the java.util.Arrays.asList() method. A program that demonstrates this is given as follows −Exampleimport java.util.ArrayList; import java.util.Arrays; import java.util.List; public class Demo { public static void main(String args[]) throws Exception { String str[] = { "John", "Macy", "Peter", "Susan", "Lucy" }; List aList = new ArrayList(Arrays.asList(str)); System.out.println("The ArrayList elements are: " + aList); } }OutputThe ArrayList elements are: [John, Macy, Peter, Susan, Lucy]Now let us understand the above program.The string array str[] is defined. Then an ArrayList is created using the ...
Read MoreReplace substring with another substring C++
Here we will see how to replace substring with another substring. It replaces the portion of the string that begins at character pos and spans len characters.The structure of the replace function is like below:string& replace (size_t pos, size_t len, const string& str, size_t subpos, size_t sublen);The parameters are pos: It is an insertion point, str : It is a string object, len : It contains information about number of characters to erase.AlgorithmStep 1: Get the main string, and the string which will be replaced. And the match string Step 2: While the match string is present in the main string: Step 2.1: Replace it with the given ...
Read MoreHow to populate a 2d array with random alphabetic values from a range in Java?
To populate a 2d array with random alphabets, use the Random class. Let us first declare a 2d array −char arr[][] = new char[3][3];Now, in a nested for loop, use the Random class object to get random values on the basis of switch case. Here, our range is 3 i.e. set of 3 alphabets at once −Random randNum = new Random(); for (int i = 0; i < 3; i++) { for (int j = 0; j < 3; j++) { int x = randNum.nextInt(3); switch (x) { case ...
Read MoreHow to convert a Date object to LocalDate object in java?
To convert a Date object to LocalDate object in Java −Convert the obtained date object to an Instant object using the toInstant() method.Instant instant = date.toInstant();Create the ZonedDateTime object using the atZone() method of the Instant class.ZonedDateTime zone = instant.atZone(ZoneId.systemDefault());Finally, convert the ZonedDateTime object to the LocalDate object using the toLocalDate() method.LocalDate givenDate = zone.toLocalDate();ExampleFollowing example accepts a name and Date of birth from the user in String formats and converts it to LocalDate object and prints it.import java.text.ParseException; import java.text.SimpleDateFormat; import java.time.Instant; import java.time.LocalDate; import java.time.ZoneId; import java.time.ZonedDateTime; import java.util.Date; import java.util.Scanner; public class DateToLocalDate { public static void main(String ...
Read MoreEnumerate through the Vector elements in Java
The Vector elements can be traversed using the Enumeration interface. The method hasMoreElements( ) returns true if there are more elements to be enumerated and false if there are no more elements to be enumerated. The method nextElement( ) returns the next object in the enumeration.A program that demonstrates this is given as follows −Exampleimport java.util.Enumeration; import java.util.Vector; public class Demo { public static void main(String args[]) { Vector vec = new Vector(); vec.add(7); vec.add(3); vec.add(5); vec.add(9); vec.add(2); ...
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