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Java Articles
Page 30 of 450
Exception Hierarchy in case of multiple catch blocks.
An exception is an issue (run time error) that occurred during the execution of a program. When an exception occurred the program gets terminated abruptly and, the code past the line that generated the exception never gets executed.Multiple exceptions in a codeWhenever we have a code that may generate more than one exception and if you need to handle them specifically you can use multiple catch blocks on a single try.try{ //code } catch(Exception1 ex1) { // } catch(Exception2 ex2) { // }Exampleimport java.util.Arrays; import java.util.Scanner; public class MultipleCatchBlocks { public static void main(String [] args) ...
Read MoreHow to read/write data from/to .properties file in Java?
The .properties is an extension in java which is used to store configurable application. It is represented by the Properties class in Java, you can store a properties file and read from it using the methods of this class. This class inherits the HashTable class.Creating a .properties file −To create a properties file −Instantiate the Properties class.Populate the created Properties object using the put() method.Instantiate the FileOutputStream class by passing the path to store the file, as a parameter.ExampleThe Following Java program creates a properties file in the path D:/ExampleDirectory/import java.io.FileOutputStream; import java.io.IOException; import java.util.Properties; public class CreatingPropertiesFile { ...
Read MoreCan I define more than one public class in a Java package?
No, while defining multiple classes in a single Java file you need to make sure that only one class among them is public. If you have more than one public classes a single file a compile-time error will be generated.ExampleIn the following example we have two classes Student and AccessData we are having both of them in the same class and declared both public.import java.util.Scanner; public class Student { private String name; private int age; Student(){ this.name = "Rama"; this.age = 29; } Student(String name, int age){ ...
Read MoreWhich packages contain Wrapper class in Java?
Java provides certain classes called wrapper classes in the java.lang package. The objects of these classes wrap primitive datatypes within them. Following is the list of primitive data types and their respective classes −Primitive datatypeWrapper classcharCharacterbyteByteshortShortintIntegerlongLongfloatFloatdoubleDoublebooleanBooleanPackageWrapper classes in Java belong to the java.lang package, Therefore there is no need to import any package explicitly while working with them.ExampleThe following Java example accepts various primitive variables from the user and creates their respective wrapper classes.import java.util.Scanner; public class WrapperClassesExample { public static void main(String args[]){ Scanner sc = new Scanner(System.in); System.out.println("Enter an integer value: ...
Read MoreHow can we split a string by sentence as a delimiter in Java?
The split() method of the String class accepts a String value representing the delimiter and splits into an array of tokens (words), treating the string between the occurrence of two delimiters as one token.For example, if you pass single space “ ” as a delimiter to this method and try to split a String. This method considers the word between two spaces as one token and returns an array of words (between spaces) in the current String.If the String does not contain the specified delimiter this method returns an array containing the whole string as an element.Examplepublic class SplitExample { ...
Read MoreHow can we check if specific string occurs multiple times in another string in Java?
You can find whether a String contains a specified sequence of characters using any of the methods −The indexOf() method − The indexOf() method of the String class accepts a string value and finds the (starting) index of it in the current String and returns it. This method returns -1 if it doesn’t find the given string in the current one.The contains() method − The contains a () method of the String class accepts a sequence of characters value and verifies whether it exists in the current String. If found it returns true else it returns false.In addition to these, you ...
Read MoreHow to trim white space in StringBuffer in Java?
The String class of the java.lang package represents a set of characters. All string literals in Java programs, such as "abc", are implemented as instances of this class. Strings objects are immutable, once you create a String object you cannot change their values, if you try to do so instead of changing the value a new object is created with the required value and the reference shifts to the newly created one leaving the previous object unused.The StringBuffer (and StringBuilder) class is used when there is a necessity to make a lot of modifications to a String.Unlike Strings, objects of ...
Read MoreHow to move files using FileUtils in Java?
Using the File classThe class named File of the java.io package represents a file or directory (pathnames) in the system. This class provides various methods to perform various operations on files/directories.This class provides various methods to manipulate files, The rename() method of the File class accepts a String representing a destination file and, renames the abstract file path of the current file to the given one.This method actually moves the file from the source path to the destination path.Exampleimport java.io.File; public class MovingFile { public static void main(String args[]) { //Creating a source file object ...
Read MoreBufferedReader class in Java.
The BufferedReader class of Java is used to read the stream of characters from the specified source (character-input stream). The constructor of this class accepts an InputStream object as a parameter.This class provides a method named read() and readLine() which reads and returns the character and next line from the source (respectively) and returns them.Instantiate an InputStreamReader class bypassing your InputStream object as a parameter.Then, create a BufferedReader, bypassing the above obtained InputStreamReader object as a parameter.Now, read data from the current reader as String using the readLine() or read() method.ExampleThe following Java program demonstrates how to read integer data ...
Read MoreWhat are variable arguments in java?
While defining a method, In general, we will specify the arguments it accepts along with the type as −myMethod(int a, String b){ }Suppose if you need to accept more than one variable of the same type you need to specify the variables one after the other as −myMethod(int a, int b, int c){ }You can also pass a variable number of arguments of a particular type, to a method. These are known as variable arguments or, varargs. They are represented by three dots (…)Syntaxpublic myMethod(int ... a) { // method body }Once you use variable arguments as a parameter ...
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