Huong Dan Java - Page 72 of 77 - Java development tutorials

Using flatMap() method of Stream object in Java

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

Sort a Map using Stream and Collectors in Java

8 years ago by Khanh NguyenJava Basic

In this tutorial, I will show you how to order elements in a Map object using the Stream object and the Collectors object in Java by key and by value. For example, we have a Map object like this:

Map<String, Integer> studentMap = new HashMap<>();
studentMap.put("Khanh", 31);
studentMap.put("Thanh", 25);
studentMap.put("Dung", 35);

Map<String, Integer> studentMap = new HashMap<>();

studentMap.put("Khanh", 31);

studentMap.put("Thanh", 25);

studentMap.put("Dung", 35);

Prior to Java 8, to… Read More

Documenting your RESTful API with Springfox for Swagger in Spring Boot

8 years ago by Khanh NguyenSpring Boot

Like RAML, the Swagger specification, or OpenAPI specification, is a specification used to define RESTful Web Service APIs. Springfox is a library used to create the RESTful API documentation in Spring, implement the Swagger specification. In this tutorial, let’s find out how to create RESTful… Read More

Specify Java version for your Eclipse

8 years ago by Khanh NguyenEclipse

Sometime, your default Java machine and your Eclipse IDE couldn’t run using same Java version. For example, your default Java machine is Java 9 but the latest Eclipse IDE can only run on Java 8. So, how can we deal with this situation? In this… Read More

Introduce about Stream in Java

8 years ago by Khanh NguyenJava Basic

Stream is a new Java object, was introduced from Java 8. It helps us can manipulate on collections and arrays easier and more efficient. So what is it? In this article, I will introduce with you all about the Stream in Java. First, consider the… Read More

Convert an object into another type using Lambda Expression and Stream in Java

8 years ago by Khanh NguyenJava Basic

Since Java 8, we have ability to convert an object into another type by using map() method of Stream object with Lambda Expression. In this tutorial, I will show to you all some examples about it. Note that, map() method is an intermediate operation in… Read More

Transaction concept in database

8 years ago by Khanh NguyenOthers

The concept of transaction in the database is an important concept that all programmers should know because we will work a lot with this concept. In this article, I would like to talk to you about this concept! For the sake of illustration, let’s take… Read More

Reset MySQL root password in macOS

8 years ago by Khanh NguyenMySQL

In this tutorial, I will show you the way to reset MySQL root password in macOS. Note: I work with MySQL 5.7.x for this tutorial, First of all, we need stop MySQL server using MySQL Start/Stop Configuration as below: Then, open Terminal and start MySQL… Read More

Filter a List using Lambda Expression and Stream in Java

8 years ago by Khanh NguyenJava Basic

Normally, before Java 8, when we want to filter a List, we will iterate through the List and base on the condition we want to filter, we can have a new List on demand. For example, I have a List containing some student names as… Read More