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Java Articles
Page 77 of 450
instanceof operator vs isInstance method in java
isInstance method is equivalent to instanceof operator. The method is used in case of objects are created at runtime using reflection. General practice says if type is to be checked at runtime then use isInstance method otherwise instanceof operator can be used. See the example below −Examplepublic class Tester{ public static void main(String[] args) throws ClassNotFoundException { Integer i = new Integer(10); System.out.println(usingInstanceOf(i)); System.out.println(usingIsInstance(i)); } public static String usingInstanceOf(Object i){ if(i instanceof String){ return "String"; } ...
Read Moreinstanceof operator vs isInstance method in java
isInstance method is equivalent to instanceof operator. The method is used in case of objects are created at runtime using reflection. General practice says if type is to be checked at runtime then use isInstance method otherwise instanceof operator can be used. See the example below −Examplepublic class Tester{ public static void main(String[] args) throws ClassNotFoundException { Integer i = new Integer(10); System.out.println(usingInstanceOf(i)); System.out.println(usingIsInstance(i)); } public static String usingInstanceOf(Object i){ if(i instanceof String){ return "String"; } ...
Read MoreIterator vs forEach in Java
Collections can be iterated easily using two approaches.Using for-Each loop − Use a foreach loop and access the array using object.Using Iterator − Use a foreach loop and access the array using object.DifferencesConcurrentModificationException − Using for-Each loop, if an object is modified, then ConcurrentModificationException can occur. Using iterator, this problem is elliminated.Size Check − Using for-Each, size check is not required. Using iterator if hasNext() is not used properly, NoSuchElementException can occur.Performance − Performance is similar for both cases.Following is an example of using above ways.Exampleimport java.util.ArrayList; import java.util.Iterator; import java.util.List; public class Tester { public static ...
Read MoreIterator vs forEach in Java
Collections can be iterated easily using two approaches.Using for-Each loop − Use a foreach loop and access the array using object.Using Iterator − Use a foreach loop and access the array using object.DifferencesConcurrentModificationException − Using for-Each loop, if an object is modified, then ConcurrentModificationException can occur. Using iterator, this problem is elliminated.Size Check − Using for-Each, size check is not required. Using iterator if hasNext() is not used properly, NoSuchElementException can occur.Performance − Performance is similar for both cases.Following is an example of using above ways.Exampleimport java.util.ArrayList; import java.util.Iterator; import java.util.List; public class Tester { public static ...
Read MoreJagged Array in Java
Jagged array is a multidimensional array where member arrays are of different size. For example, we can create a 2D array where first array is of 3 elements, and is of 4 elements. Following is the example demonstrating the concept of jagged array.Examplepublic class Tester { public static void main(String[] args){ int[][] twoDimenArray = new int[2][]; //first row has 3 columns twoDimenArray[0] = new int[3]; //second row has 4 columns twoDimenArray[1] = new int[4]; int counter = 0; ...
Read MoreJagged Array in Java
Jagged array is a multidimensional array where member arrays are of different size. For example, we can create a 2D array where first array is of 3 elements, and is of 4 elements. Following is the example demonstrating the concept of jagged array.Examplepublic class Tester { public static void main(String[] args){ int[][] twoDimenArray = new int[2][]; //first row has 3 columns twoDimenArray[0] = new int[3]; //second row has 4 columns twoDimenArray[1] = new int[4]; int counter = 0; ...
Read MorePassing and Returning Objects in Java
As we know it is core concept that in Java there is always pass by value and not by pass by reference.So in this post we will focus on that how this concept get validated in case of passing primitive and passing reference to a method.In case when a primitive type is passed to a method as argument then the value assigned to this primitive is get passed to the method and that value becomes local to that method, which means that any change to that value by the method would not change the value of primitive that you have ...
Read MoreRandom vs Secure Random numbers in Java
Java provides two classes for having random numbers generation - SecureRandom.java and Random.java.The random numbers can be used generally for encryption key or session key or simply password on web server.SecureRandom is under java.security package while Random.java comes under java.util package.The basic and important difference between both is SecureRandom generate more non predictable random numbers as it implements Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) as compare to Random class which uses Linear Congruential Generator (LCG).A important point to mention here is SecureRandom is subclass of Random class and inherits its all method such as nextBoolean(), nextDouble(), nextFloat(), nextGaussian(), nextInt() and ...
Read MoreJava program to convert float decimal to Octal number
We can convert any decimal number to its equivalent octal by following program.In this we reserve the reminder we get after divide the given number by 8 as it is the base of Octal and then reverse the order of reminders we have stored by multiplying each reminder by 10.Let understand by following example.Examplepublic class DecimalToOctal { public static void main(String[] args) { int decimal = 84; int octalNumber = 0, i = 1; while (decimal != 0) { octalNumber += (decimal % 8) * i; decimal /= 8; i *= 10; } System.out.println("Octal of given decimal is " + octalNumber); } }OutputOctal of given decimal is 124
Read MoreJava program to print duplicates from a list of integers
In order to find duplicates we can utilize the property of Set in Java that in Java duplicates are not allowed when going to be added in a Set.Add method of set returns true for the adding value which is not added previously to it while it would return false in case the adding value is already present in the Set.For our agenda we would iterate out list or collection of integer and try to add each integer in a set of type integer.Now if integer gets added than this means that it is occurring for first time and not ...
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