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Page 507 of 589
Log functions in Java
The log functions in Java are part of java.lang.Math. The functions include log, log10, log1p. Let us see an example of each of these log functions −static double log(double a)The java.lang.Math.log(double a) returns the natural logarithm (base e) of a double value. Let us see an example −Exampleimport java.io.*; public class Main { public static void main(String args[]) { // get two double numbers double x = 60984.1; double y = -497.99; // get the natural logarithm for x System.out.println("Math.log(" + x + ")=" ...
Read MoreThe new operator in Java
The new operator is used in Java to create new objects. It can also be used to create an array object.Let us first see the steps when creating an object from a class −Declaration − A variable declaration with a variable name with an object type.Instantiation − The 'new' keyword is used to create the object.Initialization − The 'new' keyword is followed by a call to a constructor. This call initializes the new object.Now, let us see an example −Examplepublic class Puppy { public Puppy(String name) { // This constructor has one parameter, name. ...
Read MoreNested Classes in Java
Writing a class within another is allowed in Java. The class written within is called the nested class, and the class that holds the inner class is called the outer class. Nested classes are divided into two types −Non-static nested classes (Inner Classes) − These are the non-static members of a class.Static nested classes − These are the static members of a class.Following are the types of Nested classes in Java −Non-static nested classes (Inner Classes)Inner classes are a security mechanism in Java. We know a class cannot be associated with the access modifier private, but if we have the class as a ...
Read MoreCheck if a value is present in an Array in Java
At first sort the array −int intArr[] = {55, 20, 10, 60, 12, 90, 59}; // sorting array Arrays.sort(intArr);Now, set the value to be searched in an int variable −int searchVal = 12;Check for the presence of a value in an array −int retVal = Arrays.binarySearch(intArr, searchVal); boolean res = retVal > 0 ? true : false;Following is an example to check if a value is present in an array −Exampleimport java.util.Arrays; public class Main { public static void main(String[] args) { // initializing unsorted int array int intArr[] = {55, 20, 10, ...
Read MoreCheck if a String starts with any of the given prefixes in Java
Let’s say the string is −String str = "Malyalam";Let’s say the prefixes are in an array −String[] prefixArr = { "Ga", "Ma", "yalam" };Now, to check whether the string starts with any of the abive prefix, use the startsWith() −if (Stream.of(prefixArr) .anyMatch(str::startsWith)) System.out.println("TRUE"); else System.out.println("FALSE");Following is an example to check is a string starts with any of the given prefixes −Exampleimport java.util.stream.Stream; class Main { public static void main(String[] args) { String str = "Malyalam"; String[] prefixArr = { "Ga", "Ma", "yalam" }; if (Stream.of(prefixArr) ...
Read MoreCheck if a string contains only alphabets in Java using ASCII values
Let’s say we have set out inut string in myStr variable. Now loop through until the length of string and check for alphabets with ASCII values −for (int i = 0; i < myStr.length(); i++) { char c = myStr.charAt(i); if (!(c >= 'A' && c = 'a' && c = 'A' && c = 'a' && c
Read MoreCheck if a string contains only alphabets in Java using Lambda expression
Let’s say our string is −String str = "Amit123";Now, using allMatch() method, get the boolean result whether the string has only alphabets or now −boolean result = str.chars().allMatch(Character::isLetter);Following is an example to check if a string contains only alphabets using Lambda Expressions −Exampleclass Main { public static void main(String[] args) { String str = "Amit123"; boolean result = str.chars().allMatch(Character::isLetter); System.out.println("String contains only alphabets? = "+result); } }OutputLet us see another example with a different input −String contains only alphabets? = falseExampleclass Main { public static void main(String[] args) ...
Read MoreIlleagalStateException Vs NoSuchElementException in java?
When you call a method at illegal or inappropriate time an IlleagalStateException is generated.For example, the remove() method of the ArrayList class removes the last element after calling the next() or previous methods.After removing the element at the current position you need to move to the next element to remove it i.e. per one call of the next() method you can invoke this remove() method only once.Since the initial position of the list (pointer) will be before the first element, you cannot invoke this method without calling the next method.If you invoke the remove() method otherwise it throws an java.lang.IllegalStateException.Example: ...
Read MoreDifference between print() and println() in Java
As we know in Java these both methods are primarily used to display text from code to console. Both these methods are of PrintStream class and are called on static member 'out' of 'System' class which is a final type class.The following are the important differences between print() and println().Sr. No.Keyprint()println()1Implementationprint method is implemented as it prints the text on the console and the cursor remains at the end of the text at the console.On the other hand, println method is implemented as prints the text on the console and the cursor remains at the start of the next line ...
Read MoreDifference between length of Array and size of ArrayList in Java
In collections, one of the main functional requirement is to get the number of elements which are get stored in our collection so that one can decide whether to put more elements in it or not. Also, the number of elements is also required for iteration of collection.As we know Array and Arraylist both are used to store elements but both have different defined methods in order to know the number of elements stored in it.The array has a length method that provides the number of elements can be stored or in simple words capacity of the Array. Also, the ...
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