Java Basic Archives - Page 11 of 13

Method takeWhile() of Stream object in Java

This method was added from Java 9.

default Stream<T> takeWhile(Predicate<? super T> predicate)

1	default Stream<T> takeWhile(Predicate<? super T> predicate)

The parameter of this method is the Predicate interface and this method takes the elements in your Stream object from left to right, until the condition of the Predicate object is no longer fulfilled. Example:

package com.huongdanjava.javastream;

import java.util.stream.Stream;

public class Example {

	public static void main(String[] args) {
		Stream.of(1,2,3,4,5,6,7,8,9,10)
			.takeWhile(i -> i < 5)
			.forEach(System.out::println);
	}
}

package com.huongdanjava.javastream;

import java.util.stream.Stream;

public class Example {

public static void main(String[] args) {

Stream.of(1,2,3,4,5,6,7,8,9,10)

.takeWhile(i -> i < 5)

.forEach(System.out::println);

}

In… Read More

Multithreading with Callable and Future in Java

8 years ago by Khanh NguyenJava Basic

Multithreading is the notion of handling program actions that do not take place in the program’s main Thread, which is handled by many different Threads. This concept will make the processing of the program faster. We have many ways to implement multithreading in Java, but… Read More

Reactive Streams in Java

8 years ago by Khanh NguyenJava Basic

Reactive Streams are a concept that defines the mechanism for handling streams asynchronously with non-blocking back pressure. Back pressure here, we can understand that there is too much work to do at the same time, then it should lead to overload. Non-blocking back pressure means… Read More

Introduce about JShell in Java

8 years ago by Khanh NguyenJava Basic

If you have ever worked with some languages like Python, Scala, you may know we can write code and execute code for those languages using only the command line. This will allow us to test some code without having to do a lot of things,… Read More

Introduction about Optional object in Java

8 years ago by Khanh NguyenJava Basic

In the previous tutorial about NullPointerException in Java, I have presented to you some cases where NPE can occur and how to deal with them to avoid. From Java 8, we have another way to avoid NullPointerException, that will use the Optional object. What is… Read More

Initialize Immutable Collections in Java

8 years ago by Khanh NguyenJava Basic

Immutable Collection likes an Immutable Object, once created, we can not edit anything on that Object or Collection. From Java 8 and earlier, to initialize an Immutable Collection like List, Set, or Map, we will use the unmodifiableXXX() methods in the java.util.Collections class. For example,… Read More

Data type of Lambda Expression in Java

8 years ago by Khanh NguyenJava Basic

In Java, we know that two types of data are primitive and object. So, Lambda Expression is defined as an anonymous function, what is its data type? In this tutorial, let’s find out together! OK, as I mentioned earlier, Lambda Expression is used with a… Read More

Talking about Serialization in Java

8 years ago by Khanh NguyenJava Basic

Serialization is a concept that allows us to convert the state of a Java object into a certain format so that this Java object can be stored somewhere and then it will be used by another process. Normally, when using Serialization, our Java object will… Read More

Using flatMap() method of Stream object in Java

8 years ago by Khanh NguyenJava Basic

When working with Stream in Java, sometime we can have a Stream with datatype of a List, Set or Array of object. For example:

List<String> students1 = new ArrayList<>();
students1.add("Khanh");

List<String> students2 = new ArrayList<>();
students2.add("Thanh");
students2.add("Dung");

List<List<String>> students = Arrays.asList(students1, students2);

Stream<List<String>> stream = students.stream();

List<String> students1 = new ArrayList<>();

students1.add("Khanh");

List<String> students2 = new ArrayList<>();

students2.add("Thanh");

students2.add("Dung");

List<List<String>> students = Arrays.asList(students1, students2);

Stream<List<String>> stream = students.stream();

Here, we have List of List of String object and when convert into Stream object, we have Stream of List… Read More

Filter a Map using Stream and Lambda Expression in Java

8 years ago by Khanh NguyenJava Basic

To filter a Map using Stream and Lambda Expression in Java, we will use the filter() method of Stream object which will be retrieved from Entry object of Map object with Lambda Expression as filter a List. How is it in details? Let learn together in… Read More