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Articles on Trending Technologies
Technical articles with clear explanations and examples
Get the list of all the public fields in Java
An array of field objects is returned by the method java.lang.Class.getFields(). These field objects include the accessible public fields of the class that is represented by the class object.Also, the getFields() method returns a zero length array if the class or interface has no public fields that are accessible 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.*; public class Demo { public static void main(String[] argv) throws Exception { Class c = java.lang.Thread.class; Field[] fields = ...
Read MoreC++ Program to Implement Sparse Matrix
A sparse matrix is a matrix in which majority of the elements are 0. An example for this is given as follows.The matrix given below contains 5 zeroes. Since the number of zeroes is more than half the elements of the matrix, it is a sparse matrix.5 0 0 3 0 1 0 0 9A program to implement a sparse matrix is as follows.Example#include using namespace std; int main () { int a[10][10] = { {0, 0, 9} , {5, 0, 8} , {7, 0, 0} }; int i, j, count = 0; int row = 3, col = 3; for (i = 0; i < row; ++i) { for (j = 0; j < col; ++j){ if (a[i][j] == 0) count++; } } cout
Read MoreRemoving a Preference from a Preference Node in Java
In order to remove a preference from a preference node in Java, we use the remove() method. The remove method() removes all the values associated with the specified key in the preference node.Declaration − The java.util.prefs.Preferences.remove() method is declared as follows −public abstract void remove (String key)where key is the key whose preference is to be removedThe remove methods throws the following exceptions −NullPointerExceptionThis exception occurs when the key is nullIllegalStateExceptionThis exception is thrown when the ancestor node is removed by the removeNode() method.Let us see a program to remove the preference from a preference node −Exampleimport java.util.prefs.Preferences; public class ...
Read MoreGregorian Calendar in Java
GregorianCalendar is a hybrid calendar that supports both the Julian and Gregorian calendar systems with the support of a single discontinuity, which corresponds by default to the Gregorian date when the Gregorian calendar was instituted.The java.util.GregorianCalendar class in Java is a concrete subclass of Calendar and provides the standard calendar system used by most of the world.Import the following package to work with GregorianCalendar class.import java.util.GregorianCalendar;The following are the constructors.Sr.No.Constructor & Description1GregorianCalendar() This constructs a default GregorianCalendar using the current time in the default time zone with the default locale.2GregorianCalendar(int year, int month, int dayOfMonth) This constructs a GregorianCalendar with the given ...
Read MoreJava Program to convert hexadecimal number to decimal number
Use the parseInt() method with the second parameter as 16 since it is the radix value. The parseInt() method has the following two forms.static int parseInt(String s) static int parseInt(String s, int radix)To convert hex string to decimal, use the 2nd syntax and add radix as 16, since hexadecimal radix is 16.Integer.parseInt("12", 16)Examplepublic class Demo { public static void main( String args[] ) { // converting to decimal System.out.println(Integer.parseInt("444", 16)); } }Output1092
Read MoreSpecify the TimeZone explicitly for Gregorian Calendar in Java
To specify the TimeZone explicitly, use the getTimeZone() method of the TimeZone class. For Locale and TimeZone, we have imported the following packages.import java.util.Locale; import java.util.TimeZoneLet us specify for timezone America/New_York.GregorianCalendar cal = new GregorianCalendar(TimeZone.getTimeZone("America/New_York"), Locale.US);The following is an example.Exampleimport java.util.GregorianCalendar; import java.util.Locale; import java.util.TimeZone; public class Demo { public static void main(String[] a) { GregorianCalendar cal = new GregorianCalendar(TimeZone.getTimeZone("America/New_York"), Locale.US); System.out.println(cal); } }Outputjava.util.GregorianCalendar[time=1542643323673, areFieldsSet=true, areAllFieldsSet=true, lenient=true, zone=sun.util.calendar.ZoneInfo[id="America/New_York", offset=-18000000, dstSavings=3600000, useDaylight=true, transitions=235, lastRule=java.util.SimpleTimeZone[id=America/New_York, offset=-18000000, dstSavings=3600000, useDaylight=true, startYear=0, startMode=3, startMonth=2, startDay=8, startDayOfWeek=1, start
Read MoreJava Program to convert octal number to decimal number
Use the parseInt() method with the second parameter as 8 since it is the radix value. The parseInt() method has the following two forms.static int parseInt(String s) static int parseInt(String s, int radix)To convert octal to decimal, use the 2nd syntax and add radix as 8, since octal radix is 8.Integer.parseInt("25", 8)The following is an example.Examplepublic class Demo { public static void main( String args[] ) { // converting to decimal System.out.println(Integer.parseInt("25", 8)); } }Output21
Read MoreDetermine 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
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