'+' operator in java can be used to add numbers and concatenate strings. Following rules should be considered.Only numbers as operands then result will be a number.Only strings as operands then result will be a concatenated string.If both numbers and strings as operands, then numbers coming before string will be treated as numbers.If both numbers and strings as operands, then numbers coming after string will be treated as a string.Above rule can be overridden using brackets().ExampleCreate a java class named Tester.Tester.javaLive Demopublic class Tester {    public static void main(String args[]) {             //Scenario 1: ... Read More

The Java.io.StringWriter class is a character stream that collects its output in a string buffer, which can then be used to construct a string. Closing a StringWriter has no effect.The Java.io.PrintWriter class prints formatted representations of objects to a text-output stream.Using these two classes you can convert a Stack Trace to a String.ExampleLive Demoimport java.io.PrintWriter; import java.io.StringWriter; public class StackTraceToString {    public static void main(String args[]) {       try {          int a[] = new int[2];          System.out.println("Access element three :" + a[3]);       } catch (ArrayIndexOutOfBoundsException e) ... Read More

ExampleYou can check if a given string is Numeric as shown in the following program.Live Demoimport java.util.Scanner; public class StringNumeric {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter a string ::");       String str = sc.next();       boolean number = str.matches("-?\d+(\.\d+)?");       if(number) {          System.out.println("Given string is a number");       } else {          System.out.println("Given string is not a number");       }    } }OutputEnter a string :: 4245 Given string is a number

The java.io.ByteArrayOutputStream.toString() method converts the stream's contents using the platform's default character set. The malformed-input and unmappable-character sequences are replaced by the default replacement string for the platform's default character set.Example Live Demoimport java.io.ByteArrayOutputStream; import java.io.IOException; public class ByteArrayOutputStreamDemo {    public static void main(String[] args) throws IOException {       String str = "";       byte[] bs = {65, 66, 67, 68, 69};       ByteArrayOutputStream baos = null;       try {          // create new ByteArrayOutputStream          baos = new ByteArrayOutputStream();          // write ... Read More

You can compare two Strings in Java using the compareTo() method, equals() method or == operator.The compareTo() method compares two strings. The comparison is based on the Unicode value of each character in the strings. The character sequence represented by this String object is compared lexicographically to the character sequence represented by the argument string.The result is a negative integer if this String object lexicographically precedes the argument string.The result is a positive integer if this String object lexicographically follows the argument string.The result is zero if the strings are equal, compareTo returns 0 exactly when the equals(Object) method would ... Read More

The FileInputStream class contains a method read(), this method accepts a byte array as a parameter and it reads the data of the file input stream to given byte array. Assume the file myData contains the following data −Exampleimport java.io.File; import java.io.FileInputStream; public class FileToByteArray {    public static void main(String args[]) throws Exception{       File file = new File("myData");       FileInputStream fis = new FileInputStream(file);       byte[] bytesArray = new byte[(int)file.length()];       fis.read(bytesArray);       String s = new String(bytesArray);       System.out.println(s);    } }OutputHi how are you welcome to Tutorialspoint

You can calculate the GCD of given two numbers, using recursion as shown in the following program.Exampleimport java.util.Scanner; public class GCDUsingRecursion {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter first number :: ");       int firstNum = sc.nextInt();       System.out.println("Enter second number :: ");       int secondNum = sc.nextInt();       System.out.println("GCD of given two numbers is ::"+gcd(firstNum, secondNum));    }    public static int gcd(int num1, int num2) {       if (num2 != 0){          return gcd(num2, num1 % num2);       } else{          return num1;       }    } }OutputEnter first number :: 625 Enter second number :: 125 GCD of given two numbers is ::125

ExampleFollowing is a program to multiply given floating point numbers.import java.util.Scanner; public class MultiplyFloatingNumbers {    public static void main(String args[]){       Scanner sc = new Scanner(System.in);       System.out.println("Enter first floating point number.");       float flt1 = sc.nextFloat();       System.out.println("Enter second floating point number.");       float flt2 = sc.nextFloat();       float product = flt1*flt2;       System.out.println("Product of given floating point numbers ::"+product);    } }OutputEnter first floating point number. 2.2 Enter second floating point number. 6.3 Product of given floating point numbers ::13.860001

The Set object provides a method known as toArray(). This method accepts an empty array as argument, converts the current Set to an array and places in the given array. To convert a Set object to an array − Create a Set object. Add elements to it. Create an empty array with size of the created Set. Convert the Set to an array using the toArray() method, bypassing the above-created array as an argument to it. Print the contents of the array.ExampleLive Demoimport java.util.HashSet; import java.util.Set; public class SetToArray {    public static void main(String args[]){       Set set = new HashSet();   ... Read More

The Map class's object contains key and value pairs. You can convert it into two list objects one which contains key values and the one which contains map values separately. To convert a map to list − Create a Map object. Using the put() method insert elements to it as key, value pairs Create an ArrayList of integer type to hold the keys of the map. In its constructor call the method keySet() of the Map class. Create an ArrayList of String type to hold the values of the map. In ... Read More