SSL Certificate generator

CertificateGenerator.java

package org.example;

import org.bouncycastle.asn1.x500.X500Name;
import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
import org.bouncycastle.cert.jcajce.JcaX509v3CertificateBuilder;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.operator.ContentSigner;
import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemWriter;

import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Security;
import java.security.cert.Certificate;
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.Date;

public class CertificateGenerator {
    public static final String provider = BouncyCastleProvider.PROVIDER_NAME;
  
    public static void main(String[] args) {
        try {
            Security.addProvider(new BouncyCastleProvider());
            KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA", provider);
            kpg.initialize(2048);
            KeyPair kp = kpg.generateKeyPair();
            X500Name x500Name = new X500Name("CN=*.choreo.dev");
            BigInteger serialNumber = BigInteger.valueOf(System.currentTimeMillis());
            String signatureAlgorithm = "SHA256WithRSA";
            ContentSigner contentSigner = new JcaContentSignerBuilder(signatureAlgorithm).build(kp.getPrivate());
            Instant startDate = Instant.now();
            Instant notBefore = startDate.plus(365, ChronoUnit.DAYS);
            JcaX509v3CertificateBuilder certificateBuilder = new JcaX509v3CertificateBuilder(x500Name,
                    serialNumber, Date.from(startDate), Date.from(notBefore), x500Name, kp.getPublic());
            Certificate certificate = new JcaX509CertificateConverter().setProvider(provider)
                    .getCertificate(certificateBuilder.build(contentSigner));

            FileOutputStream fileOutputStream = new FileOutputStream("newPrivate.key");
            FileOutputStream certOutStream = new FileOutputStream("newPublic.pem");

            var cert = new ByteArrayOutputStream();
            PemObject pop = new PemObject("CERTIFICATE", certificate.getEncoded());
            PemWriter pwp = new PemWriter(new OutputStreamWriter(cert));
            pwp.writeObject(pop);
            pwp.close();
            certOutStream.write(cert.toByteArray());
            certOutStream.close();

            var pKey = new ByteArrayOutputStream();
            PemObject po = new PemObject("PRIVATE KEY", kp.getPrivate().getEncoded());
            PemWriter pw = new PemWriter(new OutputStreamWriter(pKey));
            pw.writeObject(po);
            pw.close();
            fileOutputStream.write(pKey.toByteArray());
            fileOutputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}