1Z0–829 (Java 17) or 1Z0–830 (Java 21)? Which Oracle Java Certification to Choose in 2025?

Java 17 or Java 21 certification? which one is better for Java developer in 2025?

Hello guys, first of all, Thank you so much for great response to our new courses “Master Software Diagrams using ChatGPT, AI, and Mermaid 2025”, and Java 21 Certification Practice Tests this year as more than 150 of you joined in just few weeks.

In today’s post I am going to answer one of the most common question my reader has asked me this year, 1Z0–829 (Java 18) or 1Z0–830 (Java 21) Which certification go for in 2025?

Java remains one of the most popular programming languages, and Oracle’s Java certification exams are highly regarded among Java developers.

With the release of Java 21, Oracle introduced a new certification: Java SE 21 Developer (1Z0–830).

This raises an important question for Java professionals: Should you prepare for the Java 17 (1Z0–829) certification or the Java 21 (1Z0–830) certification in 2025?

In this article, we will compare both certifications, their key differences, exam objectives, and which one is a better choice for you in 2025.

Why Get an Oracle Java Certification in 2025?

Before diving into the comparison, let’s quickly go over why getting an Oracle Java certification is a smart move:

1. Career Advancement — Many companies prefer certified Java developers, especially for enterprise applications.
2. Proof of Expertise — Oracle certifications validate your proficiency in modern Java features.
3. Better Job Prospects — Certified developers often have an advantage in job interviews.
4. Deep Understanding of Java — Preparing for these exams helps you master Java’s core concepts.
5. Higher Salary Potential — Java certifications can help you negotiate better salaries.

I have also shared my thoughts on this topic earlier in more detail here

Why become a Certified Java Developer in 2025

Why Become a Certified Spring Professional/Developer in 2025?

Java 17 (1Z0–829) Certification Overview

Java SE 17 Developer (1Z0–829) is the official certification for Java 17, which is a Long-Term Support (LTS) version of Java. This exam replaced the older Java 11 (1Z0–819) exam and includes modern Java features.

Key Features of Java 17 Certification

• Based on Java 17, which will receive support until 2029.
• Covers modern Java concepts such as records, sealed classes, text blocks, and pattern matching.
• Requires only one exam to get certified (unlike older versions that required multiple exams).
• Recognized widely across the industry.

Java 17 Exam Topics

The 1Z0–829 exam covers:

• Java syntax and object-oriented programming
• Functional programming with lambda expressions and Streams API
• Exception handling and concurrency
• JDBC and database access
• Java I/O and NIO.2
• Security, serialization, and modular programming
• Records, sealed classes, and pattern matching

This certification is ideal for developers working with Java 17 or any LTS version in production.

Here are few more important details related to Java 17 1Z0–829 exam around number of questions and time you get to solve those questions

Java 21 (1Z0–830) Certification Overview

Java SE 21 Developer (1Z0–830) is Oracle’s latest certification, introduced with Java 21, another LTS release that will be supported until 2031.

Key Features of Java 21 Certification

• Covers all Java 17 topics, plus new features from Java 21.
• Focuses on Virtual Threads (Project Loom), Sequenced Collections, Pattern Matching for Switch, and other enhancements.
• Suitable for developers who want to work with the latest Java features.

Java 21 Exam Topics

The 1Z0–839 exam includes:

• Everything in Java 17 (1Z0–829)
• Virtual Threads for scalable concurrency
• Sequenced Collections for better data structures
• Unnamed classes and instance main methods for cleaner code
• Pattern Matching for Switch
• Structured Concurrency for better thread management

Java 21 introduces Virtual Threads, which can significantly improve performance in high-concurrency applications.

If you work in a field where performance and scalability matter (e.g., fintech, high-traffic web applications, cloud services), this certification is a strong choice.

Here are few more important details related to number of questions and time you get to solve those questions

Java 17 vs. Java 21 Certification: Which One to Choose?

Here is a nice table which compare Java 17 to Java 21 certification:

I think the key differentiator here is the difficultly level, Java 21 is significantly difficult certification to crack then Java 17 even though the number of questions have been reduced but time remains same.

Which Java Certification Should You Choose in 2025?

Now that we know what is Java 17 certification (1Z0–829) exam and what is Java 21 certification (1Z0–830) exam, its time to make the decision, which one Java developer should choose in 2025?

Choose Java 17 (1Z0–829) if:

• You work in an environment where Java 17 is the main version.
• You want a widely recognized and industry-adopted certification.
• You prefer an exam with fewer experimental features.
• You want to score high in the exam.

Choose Java 21 (1Z0–839) if:

• You want to stay ahead with cutting-edge Java features.
• Your work involves high-concurrency applications (Virtual Threads).
• You are preparing for future projects that will use Java 21 as the LTS version.

If your company is still using Java 17 or older, the Java 17 certification is a safe choice.

However, if you are working on modern applications and want to future-proof your skills, Java 21 is the better long-term investment.

You should also keep in mind that Java 21 certification is significantly tougher than Java 17 certification and there is lower chance to score high on Java 21 rather than Java 17.

So if you want to score high and want to become a Java certified developer, cracking Java 17 certification is better decision.

Here is also a nice diagram highlighting key thigns about Java 17 and Java 21 certification with their pros and points to considers like Job Market, Project Neds, and Timeline while choosing between these two Java certification.

6 Best Resources to Prepare for Java 17 and Java 21 Certifications in 2025

Regardless of which certification you choose, you’ll need solid study materials. Here are the best resources:

6.1 Best Books for Java 17 and 21 certification

1. OCP Java SE 17 Developer Study Guide by Scott Selikoff & Jeanne Boyarsky — Covers Java 17 certification topics in-depth.
2. OCP Java 17 & 21 Programmer Certification Fundamentals Part 1: 1Z0–829 1Z0–830 (OCP Java 17 / 21 Programmer Certification Exam Fundamentals Study Guide) by Hanumant Deshmukh — Will be the best resource for Java 21 certification.
3. Effective Java (3rd Edition) by Joshua Bloch — A must-read for mastering Java best practices.
4. Grokking the Java SE 17 Developer Certification (1Z0–829 Exam) book with practice questions

OCP Oracle Certified Professional Java SE 21 Developer Study Guide: Exam 1Z0–830 (Sybex Study…

OCP Oracle Certified Professional Java SE 17 Developer Certification Kit: Exam 1Z0–829

OCP Java 17 & 21 Programmer Certification Fundamentals Part 1: 1Z0–829 1Z0–830 (OCP Java 17 / 21…

Effective Java

6.2 Best Online Courses for Java 17 and Java 21 Certification

Now that we have seen the books, let’s see both online courses and practice tests you can take to prepare better for Java 17 and Java 21 certification in 2025.

For Java 17 (1Z0–829) Certification

1. Java 17 OCP Certification Course — Udemy
   A detailed course covering all Java 17 exam topics with coding exercises.
2. Java Masterclass 2025: 130+ Hours of Expert Lessons — Udemy
   Interactive learning with hands-on coding environments.
3. Java 17 1Z0–829 Practice Test — Udemy — more than 250+ practice questions with detailed answers and explanation.

For Java 21 (1Z0–830) Certification

1. Java 21: The Complete Developer’s Guide — Udemy
   Covers new Java 21 features and advanced concurrency topics.
2. Java 21 1Z0–830 Practice Test — 270+ questions

Conclusion

Both Java 17 (1Z0–829) and Java 21 (1Z0–839) certifications are excellent choices for Java developers in 2025. If you want a widely accepted and stable certification, go for Java 17.

If you want to stay ahead and learn modern Java features like Virtual Threads, Java 21 is the better option.

Whichever you choose, certification can significantly boost your Java career. Start preparing today with the right books and online courses, and you’ll be well on your way to becoming an Oracle-certified Java developer.

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