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Articles on Trending Technologies
Technical articles with clear explanations and examples
Generate 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 MoreJava Program to Match Dates
Firstly, we have considered the following two dates.SimpleDateFormat s = new SimpleDateFormat("yyyy-MM-dd"); Date d1 = s.parse("2018-10-15"); Date d2 = s.parse("2018-11-10");Now, use the compareTo() method to compare both the dates. The results are displayed on the basis of the return value.if (d1.compareTo(d2) > 0) { System.out.println("Date1 is after Date2!"); } else if (d1.compareTo(d2) < 0) { System.out.println("Date1 is before Date2!"); } else if (d1.compareTo(d2) == 0) { System.out.println("Date1 is equal to Date2!"); } else { System.out.println("How to get here?"); }Exampleimport java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; public class Demo ...
Read MoreDisplay two-digit year in Java
Use the ‘y’ date conversion character to display two-digit year.System.out.printf("Two-digit Year = %TY", d);Above, d is a date object −Date d = new Date();The following is an example −Exampleimport java.util.Date; import java.text.DateFormat; import java.text.SimpleDateFormat; public class Demo { public static void main(String[] args) throws Exception { Date d = new Date(); DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss a"); String format = dateFormat.format(d); System.out.println("Current date and time = " + format); System.out.printf("Four-digit Year = %TY", d); System.out.printf("Two-digit Year = %ty", d); ...
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 MoreDisplay three-digit day of the year in Java
Use the ‘j’ date conversion character to display three-digit day of the year.System.out.printf("Three-digit Day of the Year: %tj/%Tj", d, d);Above, d is a date object −Date d = new Date();The following is an example −Exampleimport java.util.Date; import java.text.DateFormat; import java.text.SimpleDateFormat; public class Demo { public static void main(String[] args) throws Exception { Date d = new Date(); DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss a"); String format = dateFormat.format(d); System.out.println("Current date and time = " + format); System.out.printf("Four-digit Year = %TY", d); ...
Read MoreHow to swap or exchange objects in Java?
Java uses call by value while passing parameters to a function. To swap objects, we need to use their wrappers. See the example below −Examplepublic class Tester{ public static void main(String[] args) { A a = new A(); A b = new A(); a.value = 1; b.value = 2; //swap using objects swap(a, b); System.out.println(a.value +", " + b.value); Wrapper wA = new Wrapper(a); Wrapper wB = new Wrapper(b); ...
Read MoreConvert string of time to time object in Java
Here is our string.String strTime = "20:15:40";Now, use the DateFormat to set the format for date.DateFormat dateFormat = new SimpleDateFormat("hh:mm:ss");Parse the string of time to time object.Date d = dateFormat.parse(strTime);The following is the complete example.Exampleimport java.text.DateFormat; import java.util.Date; import java.text.SimpleDateFormat; public class Demo { public static void main(String[] args) throws Exception { String strTime = "20:15:40"; DateFormat dateFormat = new SimpleDateFormat("hh:mm:ss"); Date d = dateFormat.parse(strTime); System.out.println("Resultant Date and Time = " + d); } }OutputResultant Date and Time = Thu Jan 01 20:15:40 UTC 1970
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 MoreImplement Runnable vs Extend Thread in Java
We can create Thread by either by implementing a runnable interface or by extending Thread class. Below are the detailed steps of using both ways to create Thread.Create a Thread by Implementing a Runnable InterfaceIf your class is intended to be executed as a thread then you can achieve this by implementing a Runnable interface. You will need to follow three basic steps −Step 1As a first step, you need to implement a run() method provided by a Runnable interface. This method provides an entry point for the thread and you will put your complete business logic inside this method. ...
Read MoreInfinity or exception in Java when divide by 0?
Consider the following code snippet where we divide a number by 0.Examplepublic class Tester{ public static void main(String[] args) { double d = 100; System.out.println(d/0); } }OutputInfinityNow consider the following code snippet.Examplepublic class Tester{ public static void main(String[] args) { int d = 100; System.out.println(d/0); } }OutputException in thread "main" java.lang.ArithmeticException: / by zero at Tester.main(Tester.java:5)As you've noted, the Infinity vs ArithmeticException, a different result for similar divide by zero program. The difference lies in floating point arithmetic used in first program and integer arithmetic used in second program.
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