Found 9326 Articles for Object Oriented Programming

Following example will showcase conversion of a Unicode String to UTF8 byte[] and UTF8 byte[] to Unicode byte[] using Reader and Writer classes.ExampleIOTester.javaimport java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.Reader; import java.io.Writer; import java.nio.charset.Charset; import java.text.ParseException; public class I18NTester {    public static void main(String[] args) throws ParseException, IOException {    String input = "This is a sample text" ;    InputStream inputStream = new ByteArrayInputStream(input.getBytes());    //get the UTF-8 data Reader    reader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));        //convert UTF-8 to Unicode    int data = reader.read();    while(data != ... Read More

Following program reverses an int array.Examplepublic class Tester {    public static void main(String[] args) {       int[] numbers = {1,2,3,4,5};       //swap the numbers till the midpoint comes       for (int start = 0, end = numbers.length - 1;       start

To make things simple, convert the array to list and then print it.Exampleimport java.util.Arrays; import java.util.List; public class Tester {    public static void main(String[] args) {       Integer[] numbers = {1,2,3,4,5};       List list = Arrays.asList(numbers);       System.out.println(list);    } }Output[1,2,3,4,5]

Use Arrays.copyOfRange() method to get a subarray.Exampleimport java.util.Arrays; public class Tester {    public static void main(String[] args) {       int[] array = new int[] {1, 2, 3, 4, 5};       int[] subArray = Arrays.copyOfRange(array, 0, 2);       System.out.println("Array: ");       for(int i = 0; i < array.length; i++) {          System.out.print(array[i] + " ");       }       System.out.println("Sub array: ");       for(int i = 0; i < subArray.length; i++) {          System.out.print(subArray[i] + " ");       }    } }OutputArray: 1 2 3 4 5 Sub array: 1 2

Following program shows how to remove negative numbers from an array.Exampleimport java.util.ArrayList; import java.util.Iterator; import java.util.List; public class Tester {    public static void main(String[] args) {       List objArray = new ArrayList();       objArray.clear();       objArray.add(2);       objArray.add(-3);       objArray.add(4);       System.out.println("Array before removing an element "+objArray);       Iterator iterator = objArray.iterator();                while(iterator.hasNext()) {          Integer next = iterator.next();          if(next < 0) {             iterator.remove();          }       }       System.out.println("Array after removing an element"+objArray);    } }OutputArray before removing an element [ 2, -3, 4 ] Array after removing an element [ 2, 4 ]

Array of Object class can be created which can accept any type of object. During operation on such array, instanceof operator can be used.Examplepublic class Tester {    public static void main(String[] args) {       Object[] dataArray = new Object[3];       dataArray[0] = new Integer(0);       dataArray[1] = new String("1");       dataArray[2] = new Boolean(false);       for(Object data: dataArray) {          if(data instanceof Integer) {             System.out.println(((Integer) data).intValue());          }          if(data instanceof String) {             System.out.println(data);          }          if(data instanceof Boolean) {             System.out.println(((Boolean) data).booleanValue());          }       }    } }Output0 1 false

Following program is converting an ArrayList to String[];Exampleimport java.util.ArrayList; import java.util.List; public class Tester {    public static void main(String[] args) {       List names = new ArrayList();       names.add("A");       names.add("B");       names.add("C");       String[] nameArray = names.toArray(new String[names.size()]);       for(String name: nameArray) {          System.out.println(name);       }    } }OutputA B C

Following program converts a vector into a array of String.Exampleimport java.util.Vector; public class Tester {    public static void main(String[] args) {       Vector data = new Vector();       data.add("A");       data.add("B");       data.add("C");       String[] strObjects = data.toArray(new String[data.size()]);       for(String obj: strObjects) {          System.out.println(obj);       }    } }

As list.toArray() returns an Object[], it can be converted to String array by passing the String[] as parameter. See the example below.import java.util.ArrayList; import java.util.List; public class Tester { public static void main(String[] args) { List data = new ArrayList(); data.add("A"); data.add("B"); data.add("C"); //Object[] objects = data.toArray(); String[] strObjects = data.toArray(new String[0]); for(String obj: strObjects) { System.out.println(obj); } } }OutputA B C

Use String(byte[]) constructor to convert byte[] to String.Examplepublic class Tester {    public static void main(String[] args) {       String test = "I love learning Java";       byte[] bytes = test.getBytes();       String converted = new String(bytes);       System.out.println(converted);    } }OutputI love learning Java