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Articles by Maruthi Krishna
Page 47 of 50
Reading UTF8 data from a file using Java
In general, data is stored in a computer in the form of bits (1 or, 0). There are various coding schemes available specifying the set of bytes represented by each character.Unicode (UTF) − Stands for Unicode Translation Format. It is developed by The Unicode Consortium. if you want to create documents that use characters from multiple character sets, you will be able to do so using the single Unicode character encodings. It provides 3 types of encodings.UTF-8 − It comes in 8-bit units (bytes), a character in UTF8 can be from 1 to 4 bytes long, making UTF8 variable width.UTF-16 ...
Read MoreHow to check if an URL is valid or not using Java?
The URL class of the java.net package represents a Uniform Resource Locator which is used to point a resource(file or, directory or a reference) in the worldwide web.This class provides various constructors one of them accepts a String parameter and constructs an object of the URL class. While passing URL to this method if you used an unknown protocol or haven’t specified any protocol this method throws a MalformedURLException.Similarly, the toURI() method of this class returns an URI object of the current URL. If the current URL is not properly formatted or, syntactically incorrect according to RFC 2396 this method throws ...
Read MoreRestrictions while declaring a generic (type) in Java
Generics is a concept in Java where you can enable a class, interface and, method, accept all (reference) types as parameters. In other words it is the concept which enables the users to choose the reference type that a method, constructor of a class accepts, dynamically. By defining a class as generic you are making it type-safe i.e. it can act up on any datatype.Restrictions on genericsYou cannot use generics in certain ways and in certain scenarios as listed below −You cannot use primitive datatypes with generics.class Student{ T age; Student(T age){ this.age = age; ...
Read MoreHow to find If a given String contains only letters in Java?
To verify whether a given String contains only characters −Read the String.Convert all the characters in the given String to lower case using the toLower() method.Convert it into a character array using the toCharArray() method of the String class.Find whether every character in the array is in between a and z, if not, return false.ExampleFollowing Java program accepts a String from the user and displays whether it is valid or not.import java.util.Scanner; public class StringValidation{ public boolean validtaeString(String str) { str = str.toLowerCase(); char[] charArray = str.toCharArray(); for (int i ...
Read MoreComparing Strings with (possible) null values in java?
Strings in Java represents an array of characters. They are represented by the String class.Using compareTo() methodThe compareTo() method of the String class two Strings (char by char) it also accepts null values. This method returns an integer representing the result, if the value of the obtained integer is −0: Given two Strings are equal or, null.1 or less: The current String preceeds the argument.1 or more: The current String succeeds the argument.Exampleimport java.util.Scanner; public class CompringStrings { public static void main(String args[]) { Scanner sc = new Scanner(System.in); System.out.println("Enter your first string ...
Read MoreHow to convert Date to String in Java 8?
The java.time package of Java provides API’s for dates, times, instances and durations. It provides various classes like Clock, LocalDate, LocalDateTime, LocalTime, MonthDay, Year, YearMonth etc. Using classes of this package you can get details related to date and time in much simpler way compared to previous alternatives.Java.time.LocalDate − This class represents a date object without time zone in ISO-8601 calendar system. The now() method of this class obtains the current date from the system clock.The toString() method of the LocalDate class converts the date value of the current Date object in to String and returns it.ExampleFollowing Java example accepts ...
Read MoreHow to represent fixed date like credit card expiry, YearMonth in java 8?
The java.time package of Java provides API’s for dates, times, instances and durations. It provides various classes like Clock, LocalDate, LocalDateTime, LocalTime, MonthDay, Year, YearMonth etc. Using classes of this package you can get details related to date and time in much simpler way compared to previous alternatives.Java.time.LocalDate − This class represents a date object without time zone in ISO-8601 calendar system. The now() method of this class obtains the current date from the system clock.The of() method of java.time.LocalDate class accepts three integer parameters representing and year, a month of an year, day of a month and, returns the ...
Read MoreHow to find Date after 1 week in java 8?
The java.time package of Java provides API’s for dates, times, instances and durations. It provides various classes like Clock, LocalDate, LocalDateTime, LocalTime, MonthDay, Year, YearMonth etc. Using classes of this package you can get details related to date and time in much simpler way compared to previous alternatives.Java.time.LocalDate − This class represents a date object without time zone in ISO-8601 calendar system.The now() method of this class obtains the current date from the system clock.The plus() method of the LocalDate class accepts a long value representing the amount to add and an object of the interface TemporalAmount representing the unit ...
Read MoreWhat is InputMisMatchException in Java how do we handle it?
From Java 1.5 Scanner class was introduced. This class accepts a File, InputStream, Path and, String objects, reads all the primitive data types and Strings (from the given source) token by token using regular expressions.To read various datatypes from the source using the nextXXX() methods provided by this class namely, nextInt(), nextShort(), nextFloat(), nextLong(), nextBigDecimal(), nextBigInteger(), nextLong(), nextShort(), nextDouble(), nextByte(), nextFloat(), next().Whenever you take inputs from the user using a Scanner class. If the inputs passed doesn’t match the method or an InputMisMatchException is thrown. For example, if you reading an integer data using the nextInt() method and the value ...
Read MoreWhat changes has been introduced in JDK7 related to Exception handling in Java?
Since Java 7 try-with resources was introduced. In this we declare one or more resources in the try block and these will be closed automatically after the use. (at the end of the try block)The resources we declare in the try block should extend the java.lang.AutoCloseable class.ExampleFollowing program demonstrates the try-with-resources in Java.import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class FileCopying { public static void main(String[] args) { try(FileInputStream inS = new FileInputStream(new File("E:\Test\sample.txt")); FileOutputStream outS = new FileOutputStream(new File("E:\Test\duplicate.txt"))){ byte[] buffer = new byte[1024]; ...
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