Debugging and Fixing Java 25 and Spring Boot 3 Issues with PDF Processing and JWT Authentication

Upgrading to Java 25 and the latest versions of Spring Boot introduces compatibility challenges with third-party libraries. Recently, while implementing PDF text extraction and JWT authentication, we encountered breaking changes that prevented our application from running correctly. This article outlines the issues, their root causes, and how we successfully fixed them.

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1. Issue: PDDocument.load(File) Not Recognized

Problem:

After upgrading to Apache PDFBox 3.x, our document processing component failed to load PDF files, throwing the following error:

The method load(File) is undefined for the type PDDocumentJava(67108964)

Root Cause:

In Apache PDFBox 3.x, the PDDocument.load(File) method was moved to Loader.loadPDF(File). The old method no longer exists, breaking backward compatibility.

Solution:

We updated our National ID extractor component to use Loader.loadPDF(File) instead of PDDocument.load(File).

Fixed Code:

import org.apache.pdfbox.Loader;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;

public String extractTextFromPDF(File pdfFile) {
    try (PDDocument document = Loader.loadPDF(pdfFile)) { // FIXED ✅
        PDFTextStripper stripper = new PDFTextStripper();
        return stripper.getText(document);
    } catch (IOException e) {
        System.err.println("Failed to extract text from PDF: " + e.getMessage());
        return "";
    }
}

✅ Now works seamlessly with Apache PDFBox 3.x

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2. Issue: jwtParserBuilder() Not Found in JJWT 0.12.6

Problem:

After updating to JJWT 0.12.6, our JWT utility class failed to parse tokens, throwing:

The method jwtParserBuilder() is undefined for the type JwtsJava(67108964)

Root Cause:

In JJWT 0.12.x, the method Jwts.jwtParserBuilder() was replaced by Jwts.parser().verifyWith(...). Moreover, verifyWith(SecretKey) requires an HMAC-compatible SecretKey.

Solution:

We updated our JWT utility to correctly initialize and verify tokens using the new method.

Fixed Code:

import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.security.Keys;
import java.security.Key;
import java.util.Base64;

public class JwtUtil {
    private Key signingKey;

    public void setSecretKey(String secretKey) {
        byte[] apiKeySecretBytes = Base64.getDecoder().decode(secretKey);
        this.signingKey = Keys.hmacShaKeyFor(apiKeySecretBytes);
    }

    public Claims parseClaims(String token) {
        return Jwts.parser()
                .verifyWith(signingKey) // FIXED ✅
                .build()
                .parseSignedClaims(token)
                .getPayload();
    }
}

✅ JWT parsing now works with JJWT 0.12.x!

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3. Best Practices for Future Upgrades

When upgrading to the latest Java and Spring Boot versions, consider the following:

• Check for breaking changes in third-party libraries by reading release notes.
• Use official migration guides for Spring Boot and dependency upgrades.
• Test in a separate branch before merging changes into the main codebase.
• Automate dependency version management using tools like Maven Enforcer Plugin.

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Conclusion

By troubleshooting our PDF processing and JWT authentication bugs, we learned how to adapt to Java 25, Spring Boot 3, Apache PDFBox 3.x, and JJWT 0.12.x changes. These fixes not only restored functionality but also made our application future-proof against upcoming updates.

🚀 Have you encountered similar issues? Share your experiences in the comments!