In thefirstarticle we learned about Lambdas, functional interfaces and method references introduced in Java 8. In thepreviousarticle we saw default methods in interfaces and their inheritance rules. In this article we look at the new default methods added in the Collections hierarchy. Many of the ...
All the Collections APIs work on object types, so primitives must be wrapped when stored in them. We’ll see in the next section that Java makes this wrapping process automatic. For now, however, let’s do it ourselves. As we’ll see, a List is an extensible collection of Objects. We...
HashMap, Hashtable, or WeakHashMap, make sure that the hashCode() of the key objects that you put into the collection never changes while the object is in the collection. The bulletproof way to ensure this is to make your keys immutable, which has also other benefits. ...
ArrayList vs Array: While both can store elements, ArrayList is resizable and provides built-in methods for element manipulation. Arrays are fixed-size and don’t have these built-in methods. However, arrays can be more efficient in terms of memory and access speed, especially for a large num...
In the above class, we create an instance of the Library class and add two Book objects to the collection using the “addBook()” method. We then display the books in the library using the “displayBooks()” method. We remove one of the books using the “removeBook()” method and di...
Methods inherited from class java.lang.Object getClass,notify,notifyAll,wait,wait,wait Constructor Detail CachedMethods public CachedMethods() Returns: Method setItems public void setItems(Collection<String> items) A complex type that contains the HTTP methods that you want CloudFront to cache respons...
Above code compiles fine but throws ClassCastException at runtime because we are trying to cast Object in the list to String whereas one of the element is of type Integer. After Java 5, we use collection classes like below. 1 2
Consider writing a method that takes an array of objects and a collection and puts all objects in the array into the collection. Here's a first attempt:static void fromArrayToCollection(Object[] a, Collection<?> c) { for (Object o : a) { c.add(o); // compile-time error } } ...
Suppose that your developers would like to create aComparatorinstance that enables them to sort a collection of objects in reverse order. For example, how would you sort the deck of playing cards first by descending order of rank, from Ace to Two (instead of from Two to Ace)? As before,...
Use setAuthenticationMethods(java.util.Collection) or withAuthenticationMethods(java.util.Collection) if you want to override the existing values. Parameters: authenticationMethods - An array list of authentication methods for the specified application. Returns: Returns a re...