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Java Articles
Page 105 of 450
How to schedule tasks in Java to run for repeated fixed-delay execution, beginning after the specified delay
One of the methods in the Timer class is the void schedule(TimerTask task, long delay, long period) method. This method schedules tasks for repeated fixed-delay execution, beginning after the specified delay.In fixed-delay execution, each execution is scheduled with respect to the original execution time of the preceding execution. If an execution is delayed for a particular reason (case in point, garbage collection), the subsequent executions will be delayed as well.Declaration −The java.util.Timer.schedule(TimerTask task, long delay, long period) is declared as follows −public void schedule(TimerTask task, long delay, long period)Here, task is the task to be scheduled, delay is the delay ...
Read MoreDump the content of an array in Java
An array can be easily printed by using the method java.util.Arrays.toString() in Java. This method returns a string representation of the array contents that is enclosed in square brackets. If the array is null, then this method returns null.A program that demonstrates this is given as follows −Exampleimport java.util.Arrays; public class Demo { public static void main(String args[]) { String str[] = {"John", "Harry", "Sally", "Emma", "Peter"}; System.out.println("The array content is:"); System.out.println(Arrays.toString(str)); } }OutputThe array content is: [John, Harry, Sally, Emma, Peter]Now let us understand the above program.The string ...
Read MoreReplace All Elements Of ArrayList with with Java Collections
In order to replace all elements of ArrayList with Java Collections, we use the Collections.fill() method. The static void fill(List list, Object element) method replaces all elements in the list with the specified element in the argument.Declaration −The java.util.Collections.fill() method is declared as follows −public static void fill(List
Read MoreSwap elements of ArrayList with Java collections
In order to swap elements of ArrayList with Java collections, we need to use the Collections.swap() method. It swaps the elements at the specified positions in the list.Declaration −The java.util.Collections.swap() method is declared as follows −public static void swap(List list, int i, int j)where i is the index of the first element to be swapped, j is the index of the other element to be swapped and list is the list where the swapping takes place.Let us see a program to swap elements of ArrayList with Java collections −Exampleimport java.util.*; public class Example { public static void main ...
Read MoreGet the list of all the public methods in Java
A list of all the public methods of a class or interface that is represented by an object are provided using the method java.lang.Class.getMethods(). The public methods include that are declared by the class or interface and also those that are inherited by the class or interface.Also, the getMethods() method returns a zero length array if the class or interface has no public methods or if a primitive type, array class or void is represented in the Class object.A program that demonstrates this is given as follows −Exampleimport java.lang.reflect.Method; public class Main { public static void main(String[] argv) throws ...
Read MoreDisplay the package name of a class in Java
The package for a class can be obtained using the java.lang.Class.getPackage() method with the help of the class loader of the class. If there is no package object created by the class loader of the class, then null is returned.A program that demonstrates this is given as follows −Exampleimport java.util.Date; public class Main { public static void main(String[] args) { Date d = new Date(); Package p = d.getClass().getPackage(); String pName = p.getName(); System.out.println("The package name is: " + pName); } }OutputThe package name is: java.utilNow ...
Read MoreGenerate Random Long type numbers in Java
In order to generate Random long type numbers in Java, we use the nextLong() method of the java.util.Random class. This returns the next random long value from the random generator sequence.Declaration − The java.util.Random.nextLong() method is declared as follows −public long nextLong()Let us see a program to generate random long type numbers in Java −Exampleimport java.util.Random; public class Example { public static void main(String[] args) { Random rd = new Random(); // creating Random object System.out.println(rd.nextLong()); // displaying a random long value } }Output-4787108556148621714Note - The output may vary on Online compilers.
Read MoreWhat would getPackage() return for a class in unnamed package in Java?
The package for a class can be obtained using the java.lang.Class.getPackage() method with the help of the class loader of the class.The getPackage() method returns null for a class in unnamed package. A program that demonstrates this is given as follows −Exampleclass Class1 { public class Main { public static void main(String[] argv) throws Exception { Class c = Class1.class; System.out.println(c.getPackage()); } }OutputnullNow let us understand the above program.The getPackage() method is used to obtain the package for the class. However, the getPackage() method returns null for the class ...
Read MoreCheck for the availability of a package in Java
The availability can be checked using the method java.lang.Class.forName(). The class object associated with the class with the given string name can be returned using the method java.lang.Class.forName(String name, boolean initialize, ClassLoader loader), using the class loader that is used to load the class.A program that demonstrates this is given as follows −Examplepublic class Main { public static void main(String args[]) { System.out.println(Availability("java.lang.String")); } public static boolean Availability(String name) { boolean flag = false; try { Class.forName(name, false, null); flag ...
Read MoreGet the unqualified name of a class in Java
A qualified class name in Java contains the package that the class originated from. In contrast to this, the unqualified class name contains only the class name without any package information. A program that gets the unqualified name of a class is given as follows:Examplepublic class Demo { public static void main(String[] argv) throws Exception { Class c = java.util.ArrayList.class; String className = c.getName(); System.out.println("The qualified class name is: " + className); if (className.lastIndexOf('.') < 0) { className = className.substring(className.lastIndexOf('.') + 1); ...
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