[Java] HTML (to XHTML) then to PDF with CSS 2.1 Support | Flying Saucer + OpenPDF

HtmlToPdf.java

import java.io.*;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.xhtmlrenderer.extend.FontResolver;
import org.xhtmlrenderer.pdf.ITextRenderer;

public class HtmlToPdf {
    public static void main(String[] args) throws IOException {
        String html = "<h1>hello</h1>";
        String xhtml = htmlToXhtml(html);
        xhtmlToPdf(xhtml, "output.pdf");
    }

    private static String htmlToXhtml(String html) {
        Document document = Jsoup.parse(html);
        document.outputSettings().syntax(Document.OutputSettings.Syntax.xml);
        return document.html();
    }

    private static void xhtmlToPdf(String xhtml, String outFileName) throws IOException {
        File output = new File(outFileName);
        ITextRenderer iTextRenderer = new ITextRenderer();
        FontResolver resolver = iTextRenderer.getFontResolver();
        iTextRenderer.getFontResolver().addFont("MyFont.ttf", true);
        iTextRenderer.setDocumentFromString(xhtml);
        iTextRenderer.layout();
        OutputStream os = new FileOutputStream(output);
        iTextRenderer.createPDF(os);
        os.close();
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>html-to-pdf</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>1.13</maven.compiler.source>
        <maven.compiler.target>1.13</maven.compiler.target>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>13</source>
                    <target>13</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.jsoup/jsoup -->
        <dependency>
            <groupId>org.jsoup</groupId>
            <artifactId>jsoup</artifactId>
            <version>1.13.1</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.xhtmlrenderer/flying-saucer-core -->
        <dependency>
            <groupId>org.xhtmlrenderer</groupId>
            <artifactId>flying-saucer-core</artifactId>
            <version>9.1.20</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.xhtmlrenderer/flying-saucer-pdf-openpdf -->
        <dependency>
            <groupId>org.xhtmlrenderer</groupId>
            <artifactId>flying-saucer-pdf-openpdf</artifactId>
            <version>9.1.20</version>
        </dependency>
    </dependencies>


</project>