Found 9326 Articles for Object Oriented Programming

To display the day in week, use the SimpleDateFormat(“E”) as shown below −Format f = new SimpleDateFormat("E"); String strDayinWeek = f.format(new Date()); System.out.println("Day in week = "+strDayinWeek);Since, we have used the Format and SimpleDateFormat class above, therefore import the following packages. With that, we have also used the Date.import java.text.Format; import java.text.SimpleDateFormat; import java.util.Date;Example Live Demoimport 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();       SimpleDateFormat simpleformat = new SimpleDateFormat("dd/MMMM/yyyy hh:mm:s"); ... Read More

To display two-digit day number, use the SimpleDateFormat('dd') as shown below −// displaying two-digit day number f = new SimpleDateFormat("dd"); String strDay = f.format(new Date()); System.out.println("Day Number = "+strDay);Since, we have used the Format and SimpleDateFormat class above, therefore import the following packages. With that, we have also used the Date.import java.text.Format; import java.text.SimpleDateFormat; import java.util.Date;The following is an example.Example Live Demoimport 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 More

In Java, verifying whether a string is a valid number is a common requirement in various applications. This process ensures that the string can be safely converted to a numerical type without causing runtime exceptions. To validate if a string can be converted to these types, we use the Integer.parseInt() and Float.parseFloat() methods, respectively. Problem Statement Given a string that may contain an integer or a float value, write a Java program to check whether it is valid number or not. Input "100" //string value Output 100 // ... Read More

Float is a wrapper class provided to wrap float primitive value.Let us create a Float object with float primitive.// float primitive float myFloat = 24.22f; // Float object Float obj1 = new Float(myFloat);Let us now create a Float object from string.Float obj2 = new Float("39.87");The following is an example that displays both the ways discussed above with output.Example Live Demoimport java.lang.*; public class Demo {    public static void main(String args[]) {       float myFloat = 24.22f;       Float obj1 = new Float(myFloat);       System.out.println(obj1);       Float obj2 = new Float("39.87");       System.out.println(obj2);    } }Output24.22 39.87

The isNan() method returns true if the Float value is a Not-a-Number (NaN). Let’s say we have the following Float values.Float f1 = new Float(5.0/0.0); Float f2 = new Float(10.2/0.0); Float f3 = new Float(0.0/0.0);Check with isNaN() method.f1.isNaN (); f2.isNaN (); f3.isNaN ();The following is the complete example with output.Example Live Demoimport java.lang.*; public class Demo {    public static void main(String args[]) {       Float f1 = new Float(5.0/0.0);       Float f2 = new Float(10.2/0.0);       Float f3 = new Float(0.0/0.0);       System.out.println(f1.isNaN());       System.out.println(f2.isNaN());       System.out.println(f3.isNaN());   ... Read More

To convert decimal integer to hexadecimal, use the Integer.toHexString() method. Let’s say the following is our decimal integer.int decInt = 25;The following is the usage of the Integer.toHexString() method to convert decimal integer to hexadecimal number.String myHex = Integer.toHexString(decInt);The following the complete example.Example Live Demopublic class Demo {    public static void main(String []args) {       int decInt = 25;       System.out.println("Decimal Integer = "+decInt);       String myHex = Integer.toHexString(decInt);       System.out.println("Hexadecimal = "+myHex);    } }OutputDecimal Integer = 25 Hexadecimal = 19

To convert octal to decimal number, use the Integer.parseInt() method with radix 8. Here, the radix is for Octal i.e. 8.Let’s say we have the following octal string.String myOctal = "25";To convert it to decimal, use the Integer.parseInt() method.int val = Integer.parseInt(myOctal, 8);The following is the complete example.Example Live Demopublic class Demo {    public static void main(String []args) {       String myOctal = "25";       System.out.println("Octal = "+myOctal);       int val = Integer.parseInt(myOctal, 8);       System.out.println("Decimal = "+val);    } }OutputOctal = 25 Decimal = 21

The method Integer.decode() decodes a string to an integer. It returns an Integer object holding the int value represented by the passed string value.Note − It accepts decimal, hexadecimal, and octal number.Let’s say the following is our string.String val = "2";The following is how you can decode the string to integer.Integer myInt = Integer.decode(val);Example Live Demopublic class Demo {    public static void main(String []args) {       String val = "2";       Integer myInt = Integer.decode(val);       System.out.println("Integer = " + myInt);    } }OutputInteger = 2

To convert String to long, the following are the two methods.Method 1The following is an example wherein we use parseLong() method.Example Live Demopublic class Demo {    public static void main(String[] args) {       String myStr = "5";       Long myLong = Long.parseLong(myStr);       System.out.println("Long: "+myLong);    } }OutputLong: 5Method 2The following is an example wherein we have used valueOf() and longValue() method to convert String to long.Example Live Demopublic class Demo {    public static void main(String[] args) {       String myStr = "20";       long res = Long.valueOf(myStr).longValue();       System.out.println("Long: "+res);    } }OutputLong: 20

To check for Long overflow, we need to check the Long.MAX_VALUE with the multiplied long result, Here, Long.MAX_VALUE is the maximum value of Long type in Java.Let us see an example wherein long values are multiplied and if the result is more than the Long.MAX_VALUE, then an exception is thrown.The following is an example showing how to check for Long overflow.Example Live Demopublic class Demo {    public static void main(String[] args) {       long val1 = 6999;       long val2 = 67849;       System.out.println("Value1: "+val1);       System.out.println("Value2: "+val2);       long ... Read More