Call by Value means calling a method with a parameter as value. Through this, the argument value is passed to the parameter.While Call by Reference means calling a method with a parameter as reference. Through this, the argument reference is passed to the parameter.In call by value, the modification done to the parameter passed does not reflect in the caller's scope while in call by reference, the the modification done to the parameter passed are persistent and changes are reflected in the caller's scope.But Java uses only call by value. It creates a copy of references and pass them as ... Read More

Yes, break statement can be used in nested for loops. It works on the for loop in which it is applied. See the example below.Examplepublic class Tester {    public static void main(String[] args) {       for(int i = 0; i< 2; i++) {          for(int j = 0; j < 2; j++){             if(i == 1) {                break;             }             System.out.println("i = " + i+",j = " + j);          }       }    } }

Use List.clear() method to empty an array.Exampleimport java.util.ArrayList; import java.util.List; public class Tester {    public static void main(String[] args) {       List list = new ArrayList();       list.add("A");       list.add("B");       list.add("C");       list.add("D");       list.add("E");       list.add("F");       list.add("G");       list.add("H");       System.out.println("Original List " + list);       list.clear();       System.out.println("Cleared List " + list);    } }OutputOriginal List [A, B, C, D, E, F, G, H] Cleared List []

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 example uses Contains method to search a String in the Array.Exampleimport java.util.ArrayList; public class Main {    public static void main(String[] args) {    ArrayList objArray = new ArrayList();    ArrayList objArray2 = new ArrayList();    objArray2.add(0, "common1"); objArray2.add(1, "common2");   objArray2.add(2, "notcommon"); objArray2.add(3, "notcommon1");    objArray.add(0, "common1"); objArray.add(1, "common2");    System.out.println("Array elements of array1"+objArray);    System.out.println("Array elements of array2"+objArray2);    System.out.println("Array 1 contains String common2?? " +objArray.contains("common1"));    System.out.println("Array 2 contains Array1?? " +objArray2.contains(objArray) );     }  }OutputThe above code sample will produce the following result.Array elements of array1[common1, common2] Array elements of array2[common1, common2, notcommon, notcommon1] Array ... Read More

Exampleclass Shape{     private String shapeName;     private int numSides;      Shape(String shapeName, int numSides){         this.shapeName = shapeName;         this.numSides = numSides;     }     public String toString(){         return shapeName + " has " + numSides + " sides.";     } } class ObjectList{     private Object[] list = new Object[10];     private int numElement = 0;      public void add(Object next){         list[numElement] = next;         numElement++;     }      @Override     public String toString(){         String str="";         int i=0;         while(list[i] != null){             str += list[i]+"";             i++;         }         return str;     } } public class Driver{     public static void main(String[] args){         ObjectList list = new ObjectList();         Shape square = new Shape("square", 4);         Shape hex = new Shape("hexagon", 6);         list.add(hex);         list.add(square);         System.out.println(list);     } }

You can use List.removeAll() method to filter an array. exampleimport java.util.ArrayList; import java.util.List; public class Tester {    public static void main(String[] args) {       List list = new ArrayList();       list.add("A");       list.add("B");       list.add("C");       list.add("D");       list.add("E");       list.add("F");       list.add("G");       list.add("H");       List filters = new ArrayList();       filters.add("D");       filters.add("E");       filters.add("F");       System.out.println("Original List " + list);       list.removeAll(filters);       System.out.println("Filtered List ... Read More

Use Integer.toString(int, redix) where int is byte to be converted and redix is 16 for hexadecimal format.

Following example helps to determine the upper bound of a two dimensional array with the use of arrayname.length.https://www.tutorialspoint.com/javaexamples/arrays_upperbound.htm

Following program shows how to declare a static string array.Examplepublic class Tester {    private static String[] array;    static {       array = new String[2];       array[0] = "Hello";       array[1] = "World";    }    public static void main(String[] args) {       System.out.println("Array: ");       for(int i = 0; i < array.length; i++){       System.out.print(array[i] + " ");       }    } }OutputArray: Hello World