Java Basic Archives - Page 3 of 13

Use Lambda Expression to sort elements of a List in Java

Normally, before Java 8, when we want to sort the elements of a List in Java, we will use the Comparator object. Eg:

package com.huongdanjava.javaexample;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class Example {

	public static void main(String[] args) {
		List<String> names = new ArrayList<>();
		names.add("Thanh");
		names.add("Khanh");
		names.add("Tan");

		Collections.sort(names, new Comparator<String>() {
		    @Override
		    public int compare(String s1, String s2) {
		        return s1.compareTo(s2);
		    }
		});

		for (String s : names) {
			System.out.println(s);
		}
	}
}

package com.huongdanjava.javaexample;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

public class Example {

public static void main(String[] args) {

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

names.add("Thanh");

names.add("Khanh");

names.add("Tan");

Collections.sort(names, new Comparator<String>() {

@Override

public int compare(String s1, String s2) {

return s1.compareTo(s2);

}

});

for (String s : names) {

System.out.println(s);

}

Result: From Java 8 onwards, we have another way of doing this. That is, using the sort() method of the List… Read More

Components of HotSpot JVM

5 years ago by Khanh NguyenJava Basic

Java applications run on a Java Virtual Machine (JVM) so understanding how Java applications work in the JVM will help us understand how to organize and write code more efficiently. Currently, we have a variety of JVMs built by different companies based on the JVM… Read More

Delete directory in Java

5 years ago by Khanh NguyenJava Basic

In the previous tutorial, I showed you how to create a new directory in Java. In this tutorial, I will guide you with some ways to delete a folder! The first is that we can use the File object. Deleting a directory in Java using… Read More

Constructor reference in Java

5 years ago by Khanh NguyenJava Basic

I have introduced the method reference in the previous tutorial, in this tutorial, I introduce you another new concept: constructor reference. Like the method reference, the constructor reference is used to abbreviate the Lambda Expression expression. How is it in details? Suppose you are working… Read More

Method reference in Java

5 years ago by Khanh NguyenJava Basic

Method reference is a new Java concept from version 8. It comes with Lambda Expression, which makes code writing using Lambda Expression even short but still shorter in some cases. In this tutorial, let’s learn more about the method reference in Java! OK, let’s get… Read More

Introduction about default method in Java

5 years ago by Khanh NguyenJava Basic

The default Java method introduced from Java 8 is to enable the ability to extend, improve an existing interface without breaking the previously implemented interface. How is it in details? Let’s learn together in this tutorial! OK, let’s start with the following example. For example,… Read More

Functional Interface in Java

5 years ago by Khanh NguyenJava Basic

In the Lambda Expression tutorials, I introduced you to the Functional Interface and its importance when using Lambda Expression in Java code. In this tutorial, I will talk more about Functional Interface! Definition of Functional Interface OK, let me first talk about the definition of… Read More

StringBuffer and StringBuilder in Java

5 years ago by Khanh NguyenJava Basic

In Java, in addition to the StringBuilder object, we also have a StringBuffer object with the same functionality as the StringBuilder object, but in reality it is thread-safe. This means that only one thread can access our StringBuffer object at a time. Thread-safe ensures that… Read More

Methods of the StringBuilder object in Java

5 years ago by Khanh NguyenJava Basic

In addition to the charAt(), indexOf(), substring(), length() methods that work in the String object, StringBuilder has other main methods that we’ll cover in the following: The append() method adds a value at the end of the current string of the StringBuilder object. We can… Read More

Learn about StringBuilder object in Java

5 years ago by Khanh NguyenJava Basic

We often use the StringBuilder object to build String object whose content is aggregated from a variety of conditions. In this tutorial, I will summarize the knowledge needed to work with the StringBuilder object! Initialize the StringBuilder object StringBuilder gives us 4 constructors to initialize… Read More