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How to Convert Stream to ArrayList in Java 8 - Collectors.toCollection() Example, Tutorial

You can use Collectors.toList(), toSet() and toMap() to get all elements of Stream into any Collection e.g. List, Set or Map, but if you want to get a particular collection e.g. ArrayList, then you need to use Collectors.toCollection(ArrayList::new) method. This method first creates an ArrayList using method reference and then adds all elements of Stream into the ArrayList. It's very useful if you have a long list of String and you want to create a smaller list containing only String starting with the letter "b" e.g. "Bluehost". All you need to do is first get the stream from List by calling stream() method, then call the filter() method to create a new Stream of filtered values and finally call the Collectors.toCollection(ArrayList::new) to collect those elements into an ArrayList.

3 Examples to Loop Through a List in Java 8

3 ways to Loop through a List in Java
There are multiple ways to traverse or loop through a List in Java e.g. by using an Iterator, by using an enhanced for loop of Java 5, and not the forEach() method of Java 8. Given a List is an index-based collection if you know the index you can retrieve an object from List and because of this, you can also use traditional for loop which keeps count for iterating List. Now the question is whether should you use the Iterator or enhanced for loop, or the forEach() method of Java 8 for looping over List in Java. 

Default Methods, Multiple Inheritance and Diamond Problem in Java 8

Ever since Java 8 introduced default and static methods in JDK 8, it's become possible to define non-abstract methods in interfaces. Since Java, one class can implement multiple interfaces and because there can be concrete methods in interfaces, the diamond problem has surfaced again. What will happen if two interfaces have methods o the same name and a Java class inherit from it? Many Java programmer also asks me the question that, is Java 8 is also supporting multiple inheritances of classes? Well, it's not but the doubt is genuine because the interface with methods is similar to an abstract class or in that any Class in Java.

How to convert Date to LocalDateTime in Java 8 - Example Tutorial

The LocalDateTime class has introduced in Java 8 to represents both date and time value. It's local, so date and time are always in your local time zone. Since the java.util.Date has been widely used everywhere in many Java applications, you will often find yourself converting java.util.Date to LocalDate, LocalTime and LocalDateTime classes of the java.time package. Earlier I have shown you how to convert Date to LocalDate and today, I am going to teach you how to convert Date to LocalDateTime in Java 8. The approach is the same. Since the equivalent class of java.util.Date in new Date and Time API is java.time.Instant, we first convert Date to Instance and then create LocalDateTime instance from that Instant using System's default timezone.