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Java Articles
Page 78 of 450
Referencing Subclass objects with Subclass vs Superclass reference
In java inheritance some of the basic rules includes −Object relation of Superclass (parent) to Subclass (child) exists while child to parent object relation never exists.This means that reference of parent class could hold the child object while child reference could not hold the parent object.In case of overriding of non static method the runtime object would evaluate that which method would be executed of subclass or of superclass.While execution of static method depends on the type of reference that object holds.Other basic rule of inheritance is related to static and non static method overriding that static method in java ...
Read MoreCompare two Strings lexicographically in Java programming
We can compare two strings lexicographically using following ways in Java.Using String.compareTo(String) method. It compares in case sensitive manner.Using String.compareToIgnoreCase(String) method. It compares in case insensitive manner.Using String.compareTo(Object) method. It compares in case sensitive manner.These methods returns the ascii difference of first odd characters of compared strings.Examplepublic class Tester { public static void main(String args[]) { String str = "Hello World"; String anotherString = "hello world"; Object objStr = str; System.out.println( str.compareTo(anotherString) ); System.out.println( str.compareToIgnoreCase(anotherString) ); System.out.println( str.compareTo(objStr.toString())); } }Output-32 0 0
Read MoreCount the Number of matching characters in a pair of Java string
In order to find the count of matching characters in two Java strings the approach is to first create character arrays of both the strings which make comparison simple.After this put each unique character into a Hash map.Compare each character of other string with created hash map whether it is present or not in case if present than put that character into other hash map this is to prevent duplicates.In last get the size of this new created target hash map which is equal to the count of number of matching characters in two given strings.Exampleimport java.util.HashMap; public class MatchingCharacters ...
Read MoreDifference between TreeMap, HashMap and LinkedHashMap in Java programming
HashMap, TreeMap and LinkedHashMap all implements java.util.Map interface and following are their characteristics.HashMapHashMap has complexity of O(1) for insertion and lookup.HashMap allows one null key and multiple null values.HashMap does not maintain any order.TreeMapTreeMap has complexity of O(logN) for insertion and lookup.TreeMap does not allow null key but allow multiple null values.TreeMap maintains order. It stores keys in sorted and ascending order.LinkedHashMapLinkedHashMap has complexity of O(1) for insertion and lookup.LinkedHashMap allows one null key and multiple null values.LinkedHashMap maintains order in which key-value pairs are inserted.Exampleimport java.util.HashMap; import java.util.Hashtable; import java.util.LinkedHashMap; import java.util.Map; import java.util.TreeMap; public class Tester { ...
Read MoreDifference between x++ and x= x+1 in Java programming
x++ automatically handles the type casting where as x= x + 1 needs typecasting in case of x is not an int variable. See the example below.Examplepublic class Tester { public static void main(String args[]) { byte b = 2; //Type casting is required //as 1 is int and b is byte variable b = (byte) (b + 1); System.out.println(b); byte b1 = 2; //Implcit type casting by the compiler b1++; System.out.println(b1); } }Output3 3
Read MoreFibonacci of large number in java
Fibonacci numbers of Fibonacci series grows exponentially and can be very large for large numbers like 500 or 1000. To handle such number, long data type is not sufficient. BigInteger can handle large number easily. BigInteger is useful in scenarios where calculations results in data which is out of limit for available primitive data types. See the example below of getting Fibonacci number of 100 and 1000.Exampleimport java.math.BigInteger; public class Tester { public static void main(String args[]) { System.out.println("Fibonacci of 100: "); System.out.println(fibonacci(100)); System.out.println("Fibonacci of 1000: "); ...
Read MoreFind frequency of each word in a string in Java
In order to get frequency of each in a string in Java we will take help of hash map collection of Java.First convert string to a character array so that it become easy to access each character of string.Now compare for each character that whether it is present in hash map or not in case it is not present than simply add it to hash map as key and assign one as its value.And if character is present than find its value which is count of occurrence of this character in the string (initial we put as 1 when it ...
Read MoreDisplay the minimum and maximum value of primitive data types in Java
Every data type in Java has a minimum as well as maximum range, for example, for Float.Min = 1.4E-45 Max = 3.4028235E38Let’s say for Float, if the value extends the maximum range displayed above, it leads to Overflow.However, if the value is less than the minimum range displayed above, it leads to Underflow.The following is the Java Program to display the minimum and maximum value of primitive data types.Examplepublic class Demo { public static void main(String[] args) { System.out.println("Integer Datatype values..."); System.out.println("Min = " + Integer.MIN_VALUE); System.out.println("Max = " + ...
Read MoreOverflow of DataTypes in Java
Overflow occurs when the given value is more than the maximum prescribed size of a data type. The overflow condition can result to an error or now the implementation of the programming language handles it on its own.To display overflow of datatypes, I have taken an example of float datatype. Float data type is a single-precision 32-bit IEEE 754 floating point.The range of a float datatype is −approximately ±3.40282347E+38FThe following program display overflow of datatypes in Java.Examplepublic class Demo { public static void main(String[] args) { System.out.println("Displaying Overflow... "); float val1 = 3.3976835E38f; ...
Read MoreBoolean Type in Java
To display Boolean type, firstly take two variables and declare them as boolean.boolean val1, val2;Then one by one assign values to both of them, one of them is shown below −val1 = true;Now, use if statement to check and display the Boolean true value.if(val1) System.out.println("This is true and will get displayed!");Let us now see the complete example to work with Boolean Type in Java.Examplepublic class Demo { public static void main(String[] args) { boolean val1, val2; System.out.println("Boolean Type in Java"); val1 = true; if(val1) ...
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