Finally, a correct version of classic “Hello world!” program.
import static org.assertj.core.api.Assertions.assertThat;
import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import org.junit.jupiter.api.Test;
public class HelloWorld {
@Test
void testMainPrintsHelloWorld() {
// given
final var out = new ByteArrayOutputStream();
System.setOut(new PrintStream(out));
// when
HelloWorld.main();
// then
assertThat(out.toString()).isEqualTo("Hello world!");
}
public static void main(final String... args) {
System.out.print("Hello world!");
}
}
After over one year use and collecting pretty big document base (over 1G) I can measure/profile running application.
Even a page without images takes over 1.5MB for each round-trip
Each server round-trip takes more than 1.5 MB traffic. All the scripts and other static resources are being downloaded over and over again. Browser cache doesn’t really work because of secure connection limitations. HTTPS requests are not being cached on client side. Probably because of custom SSL certificate.
Anyway, I have decided to give a try to Vue.js and dramatically refactor whole application front end.
Long story short: I have successfully managed it. Performance has been definitely increased. Back end API improved, better structured and even simplified at important points.
Here are the problems to solve when switching from classic web to SPA (single-page application):
An SPA framework required for front-end. UI programming is more complicated
UI components are being defined on front end side as well. Complex javascript file structure is required
Server should be organised to deliver 3 types of resources:
Static resources (images, styles, scripts)
Dynamic API (for communication over AJAX/REST requests)
Page addresses (specially configured for SPA) – which are visible URLs in browser
Create new Maven project or open a Java project and add Maven Nature to it.
When you add new dependencies to the project (in pom.xml), Eclipse automatically downloads all required libraries (in JAR files) into Maven repository and sets appropriate links to the files in the project build path.
So the application can be started directly from Eclipse in standard way: Use “Run as Java application” menu item for your main class.
We will not use “Export to runnable JAR file” function of the Eclipse to create a JAR for our application. We will create this file using Maven ‘install’ goal instead. Continue reading →
