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Articles on Trending Technologies
Technical articles with clear explanations and examples
Determine if a Preference Node exists in Java
In order to determine the existence a preference node in Java, we use the nodeExists() method. The nodeExists() method returns a boolean value. It returns true when the specified preference node exists in the same tree as this node.Declaration − The java.util.prefs.Preferences.remove() method is declared as follows −public abstract boolean nodeExists(String pathname)throws BackingStoreExceptionwhere pathname is the path name of the node whose existence needs to be determined.Let us see a program to determine if a preference node exists in Java −Exampleimport java.util.prefs.Preferences; public class Example { public static void main(String[] args) throws Exception { boolean exist ...
Read MoreDisplay the maximum amount of memory in Java
In order to display the maximum amount of memory in Java, we use the maxMemory() method. It is a method of the java.lang.Runtime Class. It returns the maximum amount of memory that the Java Virtual Machine will try to use.Declaration − The java.lang.Runtime.maxMemory() method is declared as follows −public long maxMemory()Let us see a program to display the maximum amount of memory in Java −Examplepublic class Example { public static void main(String[] args) { // print statement at the start of the program System.out.println("Start..."); // displays the maximum memory ...
Read MoreJava Program to convert decimal integer to hexadecimal number
Use the toHexString() method to convert decimal to hexadecimal. The method returns a string representation of the integer argument as an unsigned integer in base 16. The following characters are used as hexadecimal digits:0123456789abcdef.The following is the syntax.String toHexString(int i)It has only single parameter.i − This is an integer to be converted to a string.Examplepublic class Demo { public static void main( String args[] ) { int dec = 45; System.out.println("Decimal = "+dec); // converting to hex System.out.println(Integer.toHexString(dec)); } }OutputDecimal = 45 2d
Read MoreSet the Date and Time with Gregorian Calendar in Java
To work with the GregorianCalendar class, import the following package.import java.util.GregorianCalendar;Create a Date object.Date d = new Date();Now, create an object and set the time using the setTime() method.GregorianCalendar cal = new GregorianCalendar(); cal.setTime(d);The following is an example.Exampleimport java.util.Date; import java.util.GregorianCalendar; public class Demo { public static void main(String[] a) { Date d = new Date(); GregorianCalendar cal = new GregorianCalendar(); cal.setTime(d); System.out.println(d); } }OutputMon Nov 19 16:11:31 UTC 2018
Read MoreDisplay the amount of free memory in the Java Virtual Machine
In order to display the amount of free memory in the Java Virtual Machine, we use the freeMemory() method. It is a method of the java.lang.Runtime Class. It returns the amount of free memory in the Java Virtual Machine. If we call the gc method, there is a possibility of increase of free memory.Declaration − The java.lang.Runtime.freeMemory() method is declared as follows −public long freeMemory()Let us see a program to display the amount of free memory in the Java Virtual Machine −Examplepublic class Example { public static void main(String[] args) { // print statement at the ...
Read MoreHow to convert Decimal to Hexadecimal in Java
To convert decimal to hexadecimal, use any of the two methods i.e.Integer.toHexString() − It returns a string representation of the integer argument as an unsigned integer in base 16.Integer.parseInt() − It allows you to set the radix as well, for example, for hexadecimal set it as 16.Let us see an example now to convert decimal to hexadecimal using Integer.toHexString() method.Examplepublic class Demo { public static void main( String args[] ) { int dec = 158; System.out.println(Integer.toHexString(dec)); } }Output9eLet us see an example now to convert decimal to hexadecimal using Integer.parseInt() method.Examplepublic class ...
Read MoreSet a GregorianCalendar object to a particular date in Java
To work with the GregorianCalendar class, import the following package.import java.util.GregorianCalendar;Firstly, create a GregorianCalendar object.GregorianCalendar calendar = new GregorianCalendar();Now, set the above-created object to a date. Here 0 is for 1st month.calendar.set(2018, 0, 25);The following is an example.Exampleimport java.util.GregorianCalendar; import java.util.Calendar; import java.util.Date; public class Demo { public static void main(String[] args) { GregorianCalendar calendar = new GregorianCalendar(); // 0 is for 1st month calendar.set(2018, 0, 25); System.out.println("" + calendar.getTime()); } }OutputThu Jan 25 16:51:24 UTC 2018
Read MoreDisplay TimeZone in zzzz format in Java
Use the zzzz format like this for TimeZone.SimpleDateFormat("zzzz");Let us see an example −// displaying timezone in zzzz format simpleformat = new SimpleDateFormat("zzzz"); String strTimeZone = simpleformat.format(new Date()); System.out.println("TimeZone in zzzz format = "+strTimeZone);Above, we have used the SimpleDateFormat class, therefore the following package is imported −import java.text.SimpleDateFormat;The following is an example −Exampleimport java.text.Format; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Calendar; public class Demo { public static void main(String[] args) throws Exception { // displaying current date and time Calendar cal = Calendar.getInstance(); ...
Read MoreGet number of available processors in Java
In order to get the number of available processors in Java, we use the availableProcessors() method. The java.lang.Runtime.availableProcessors() method returns the number of processors which are available to the Java virtual machine. This number may vary during a particular call of the virtual machine.Declaration − The java.lang.Runtime.availableProcessors() method is declared as follows −public int availableProcessors()Let us see a program to get the number of available processors in Java −Examplepublic class Example { public static void main(String[] args) { // print statement at the start of the program System.out.println("Start..."); System.out.print("Number of ...
Read MoreJava Program to get the day of the week from GregorianCalendar
For GregorianCalendar class, import the following package.import java.util.GregorianCalendar;Create an object.GregorianCalendar calendar = new GregorianCalendar();To get the day of the week, use the following field.GregorianCalendar.DAY_OF_WEEKThe following is an example.Exampleimport java.util.Calendar; import java.util.GregorianCalendar; public class Demo { public static void main(String[] a) { GregorianCalendar calendar = new GregorianCalendar(); System.out.println("Day of Week = " + calendar.get(GregorianCalendar.DAY_OF_WEEK)); System.out.println("Date = " + calendar.get(GregorianCalendar.DATE)); System.out.println("Month = " + calendar.get(GregorianCalendar.MONTH)); System.out.println("Year = " + calendar.get(GregorianCalendar.YEAR)); } }OutputDay of Week = 2 Date = 19 Month = 10 Year = 2018
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