From Amazon's description:
"Patches and improvements in Corretto enable Amazon to address high-scale, real-world service concerns, meeting heavy performance and scalability demands. We’re making these available to customers with no-cost, long-term support, with quarterly updates including bug fixes and security patches. AWS will also provide urgent fixes to customers outside of the quarterly schedule"
So Corretto has tweaks that are specific to performance (e.g. for server or cloud applications), and also additional bug fixes that users can take advantage of that aren't necessarily in OpenJDK proper yet. Also with this Amazon is offering proper LTS support of their build, as other commercial companies are starting to do for the JDK (Oracle and Azul come to mind, as well as others).
Answer from Jason on Stack OverflowFrom Amazon's description:
"Patches and improvements in Corretto enable Amazon to address high-scale, real-world service concerns, meeting heavy performance and scalability demands. We’re making these available to customers with no-cost, long-term support, with quarterly updates including bug fixes and security patches. AWS will also provide urgent fixes to customers outside of the quarterly schedule"
So Corretto has tweaks that are specific to performance (e.g. for server or cloud applications), and also additional bug fixes that users can take advantage of that aren't necessarily in OpenJDK proper yet. Also with this Amazon is offering proper LTS support of their build, as other commercial companies are starting to do for the JDK (Oracle and Azul come to mind, as well as others).
Other than any performance benefits, an important reason to use Corretto is for its Long Term Support of its releases, including security vulnerabilities.
One of the important differences between OpenJDK and several other vendors (like Amazon Corretto) is their release and support cycle.
OpenJDK is on a 6-month release cycle and only support each release for this time. After the next release, the previous release will stop receiving patches. This means to stay up to-to-date, you must upgrade every 6 months.
Corretto on the other hand offers LTS (Long Term Support) of their JDK builds.
Amazon Corretto is a no-cost, multiplatform, production-ready distribution of the Open Java Development Kit (OpenJDK) that comes with long-term support (LTS). LTS includes Amazon’s commitment to provide performance enhancements and security updates at no cost until at least the specified date for the relevant release version (e.g. May 2026 for Corretto 8). Updates are planned to be released quarterly. Amazon also plans to apply urgent fixes (including security) outside of the regular quarterly cycle when they are available and ready to use.
To summarize, you have 3 options:
- Use OpenJDK for free, but upgrade every 6 months to get updates
- Use a paid JDK from Oracle or another vendor
- Use Corretto for free, and get free updates for several years
As you can see, Corretto is a great choice if you want to stay secure and up-to-date, don't want to pay money, and don't want to be constantly upgrading to a new version.
Here are the current end of life dates for Corretto:
- version 8 LTS June 2026
- version 11 LTS September 2027
- version 17 LTS October 2029
Non-LTS versions are available as well, but are supported for a shorter period of time.
The is a variety of JDK vendors out there, so there may be other alternatives for a free and updated JDK, but be sure to read the vendors website carefully to understand their support and patching policy. Personally I think Corretto is a great choice, and something you can be confident will be patched in a timely manner.
What is the differences between Amazon Corretto and Java JDK? Why we use Amazon Corretto for specially developing Enterprise Apps? - Stack Overflow
java - OpenJdk LTS vs AWS Corretto - both offer LTS, Corretto seam to be 4 yrs behind? - Stack Overflow
What is the difference of openjdk 11 vs Amazon Corretto 11 in 2022? - Stack Overflow
Java 11 for AGP 7
Backed by Amazon
Corretto comes with no-cost, long-term support from Amazon, so you can upgrade versions only when you need to. Amazon is committed to Corretto, running it internally on thousands of production services.
Multiplatform support
Production ready
Videos
We're a little weary of patching the Java runtime (the component leveraged by locally installed Java client when they visit a Java-enabled webpage). We've tried some very basic testing of [Corretto] (https://aws.amazon.com/corretto/?filtered-posts.sort-by=item.additionalFields.createdDate&filtered-posts.sort-order=desc) as a locally installed alternative but even though we've set the environment variables (windows), we've not had any luck. It seems web-based applications still 'look for' traditional Java installed. Has anyone had any luck? What are we overlooking? Thanks in advance..
but OpenJDK also has LTS support (8, 11, 17, ..)
Be careful with your use of names here.
OpenJDK is the name of an open-source project. That project implements the Java specifications published by Oracle. The OpenJDK project is owned by Oracle Corp but enjoys the contributions of code and labor by IBM, Apple, and other companies and individuals.
The OpenJDK project provides only source code. For executable builds of that software, and installers for that software, you must look elsewhere. Several vendors offer binaries and installers.
The confusion comes from the fact that Oracle Corp legally allows vendors to use the word “OpenJDK” in the name of their JDK products. This naming represents the fact that their product is based largely (if not entirely) on the OpenJDK source code.
what is the point of using Corretto
You have a choice of obtaining a JDK (implementation of the Java specs) from several vendors. You may have various reasons motivating your choice. One reason might be the possibility of purchasing a support plan. Another reason might be needing an implementation for a particular less-common platform. Another reason might be convenience, or familiarity with the vendor.
Some folks choose AWS Corretto because they intend to deploy on AWS cloud. Amazon promises to keep Corretto as close as is practicable to the same as what executes on the AWS cloud.
Why is Corretto so behind given that OpenJDK LTS is 17 and Correto is based on OpenJdk 11?
As explained well in the Answer by dave_thompson_085, your understanding of those versions is incorrect.
Amazon maintains releases of Corretto for all three long-term support (LTS) versions of Java: 8, 11, and 17. Amazon also has a release for the current version of Java, 19.
The version number of each Corretto release corresponds with the version of Java specs being implemented, as noted on their GitHub site.
Amazon Corretto currently provides 8 11 and 15 to 19 (including 17). More completely it follows Oracle and (at least most) other OpenJDK packagers by supporting designated LTS versions 8 11 17 long-term, but non-LTS versions only for a limited period (so 15 and 16 should go away soonish as 20 and 21 are added). Major version 11 was initially released in 2018 but the most recent maintenance aka patch version of 11 from Corretto is 11.0.17.8.1 just a few months ago, approximately the same as Oracle (my current Oracle 11 identifies as 11.0.17+10-LTS-269).