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Articles on Trending Technologies
Technical articles with clear explanations and examples
Use a quantifier to find a match in Java
One of the quantifiers is the plus(+). This matches one or more of the subsequence specified with the sequence.A program that demonstrates using the quantifier plus(+) to find a match in Java is given as follows:Exampleimport java.util.regex.Matcher; import java.util.regex.Pattern; public class Demo { public static void main(String args[]) { Pattern p = Pattern.compile("o+"); Matcher m = p.matcher("o oo ooo"); System.out.println("The input string is: o oo ooo"); System.out.println("The Regex is: o+ "); System.out.println(); while (m.find()) { System.out.println("Match: " ...
Read MoreThe toArray() method of CopyOnWriteArrayListin Java
The toArray() method is used to return an array containing all the elements in this list in proper sequence.The syntax is as follows −Object[] toArray()To work with CopyOnWriteArrayList class, you need to import the following package −import java.util.concurrent.CopyOnWriteArrayList;The following is an example to implement CopyOnWriteArrayList class toArray() method in Java−Exampleimport java.util.Arrays; import java.util.concurrent.CopyOnWriteArrayList; public class Demo { public static void main(String[] args) { CopyOnWriteArrayList arrList = new CopyOnWriteArrayList(); arrList.add(220); arrList.add(250); arrList.add(400); ...
Read MoreC++ Program to Find Size of the Largest Independent Set(LIS) in a Given a Binary Tree
This is a C++ Program to Find Size of the Largest Independent Set (LIS) in a Given a Binary Tree.AlgorithmBegin. Create a structure n to declare data d, a left child pointer l and a right child pointer r. Call a function max() to return maximum between two integers. Create a function LIS() to return the size of the largest independent set in a given binary tree. Calculate size excluding the current node int size_excl = LIS(root->l) + LIS(root->r) Calculate size including the current node int size_incl = 1; if (root->l) ...
Read MoreJava Program to sort a subset of array elements
Let us first create a string array −String[] strArr = new String[] { "r", "p", "v", "y", "s", "q" };Now, use Arrays.sort() to get the subset. Use the following to sort only from the index range 2 to 6.Arrays.sort(strArr, 2, 6);Exampleimport java.util.Arrays; public class Demo { public static void main(String[] args) { String[] strArr = new String[] { "r", "p", "v", "y", "s", "q" }; Arrays.sort(strArr, 2, 6); System.out.println("Sorted subset of array elements from index 2 to 6..."); for (int a = 0; a < strArr.length; a++) ...
Read MoreCreate a TreeSet in Java
Create a TreeSet and add elements −TreeSet tSet = new TreeSet(); tSet.add("TV"); tSet.add("Radio"); tSet.add("Internet");Iterate through the elements −Iterator i = tSet.iterator(); while(i.hasNext()){ System.out.println(i.next()); }The following is an example to create a TreeSet −Exampleimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet tSet = new TreeSet(); tSet.add("TV"); tSet.add("Radio"); tSet.add("Internet"); Iterator i = tSet.iterator(); while(i.hasNext()){ System.out.println(i.next()); } } }OutputInternet Radio TV
Read MoreLoop through the Vector elements using an Iterator in Java
An Iterator can be used to loop through the Vector elements. The method hasNext( ) returns true if there are more elements in the Vector and false otherwise. The method next( ) returns the next element in the Vector and throws the exception NoSuchElementException if there is no next element.A program that demonstrates this is given as follows −Exampleimport java.util.Iterator; import java.util.Vector; public class Demo { public static void main(String args[]) { Vector vec = new Vector(); vec.add(4); vec.add(1); vec.add(3); vec.add(9); ...
Read MoreMake a class final in Java
A class can be made final by using the final keyword. The final class cannot be inherited and so the final keyword is commonly used with a class to prevent inheritance.A program that demonstrates a final class in Java is given as follows:Examplefinal class A { private int a = 15; public void printA() { System.out.println("Value of a = " + a); } } public class Demo { public static void main(String args[]) { A obj = new A(); obj.printA(); } }OutputValue of a = 15Now ...
Read MoreHow many times finalize method will be invoked? who invokes finalize() method in Java?
The finalize() method belongs to the Object class. Right before closing an object, the garbage collector makes sure that there are no more references to it and, calls the finalize() method on it.Therefore, once you override the finalize() method in it, you can do all the cleanup activity like closing the resources like database connection, network connection, etc.protected void finalize throws Throwable{}It is invoked only once during the execution of a program.Following are some notable points about the finalize method.Since this method belongs the Object class, which is the super class of all the classes in java, you can override ...
Read MoreWhy Abstract Class is used in Java?
A class is an abstract class if it contains at least one abstract method. It can contain other non-abstract methods as well. A class can be declared as abstract by using the abstract keyword. Also, an abstract class cannot be instantiated.A program that demonstrates an abstract class in Java is given as follows:Exampleabstract class Animal { abstract void sound(); } class Cat extends Animal { void sound() { System.out.println("Cat Meows"); } } class Dog extends Animal { void sound() { System.out.println("Dog Barks"); } } class Cow extends Animal { ...
Read MoreLongStream summaryStatistics() method in Java
The summaryStatistics() method in the LongStream class in Java returns a LongSummaryStatistics describing various summary data about the elements of this stream.The syntax is as follows −LongSummaryStatistics summaryStatistics()Here, LongSummaryStatistics is a state object for collecting statistics such as count, min, max, etc.To use the LongStream class in Java, import the following packageimport java.util.stream.LongStream;Create LongStream and add some elements −LongStream longStream = LongStream.of(30000L, 15000L, 20000l, 25000l, 30000l);Now, get the statistics −LongSummaryStatistics info = longStream.summaryStatistics(); The following is an example to implement LongStream summaryStatistics() method in Java −Exampleimport java.util.stream.LongStream; import java.util.LongSummaryStatistics; public class Demo { public static void ...
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