Excelsior JET - Java Virtual Machine (JVM) and Native Code Compiler

What Is It?

Excelsior JET is a complete implementation of the Java SE technology for Microsoft Windows, Apple OS X, and Linux. It includes:

Java SE 8 compatible JVM
Ahead‑Of‑Time (AOT)
Java to native code compiler
Complete Java SE 8 and JavaFX 8 API implementations, licensed from Oracle
Deployment toolkit

Excelsior JET has passed the official compliance tests (JCK) and is certified Java Compatible.

How It Works

First, the AOT compiler turns your jar and class files into a conventional binary executable. That executable is fully interoperable with our JVM, which includes a JIT compiler to handle any classes that were not precompiled.

Second, the deployment toolkit helps you create an installer containing the application executable, necessary runtime files, and the auxiliary files of your choice — data files, documentation, license, etc.

Look under the hood »

Data Sheet | Frequently Asked Questions | Changelog | Roadmap

You may be wondering what it takes to get this little Java Compatible logo and, more importantly, what benefits it delivers to you as a user of our product. These are the key points:

Shapes and holes

Excelsior JET has passed the Java SE 8 Technology Compatibility Kit (JCK) test suite.

The JCK comprises over 200,000 individual test cases verifying compliance with all aspects of the Java specification. Technically, this means that any program coded in accordance with the Java specification must produce the same result on the reference implementation and when natively compiled with Excelsior JET.

The standard Java SE class library included in Excelsior JET is built from the same source code as the one included in the Oracle JRE.

The reuse of the reference implementation source code not only has helped our product pass the JCK tests. It also makes Excelsior JET replicate any loosely specified or implementation-defined behavior of the standard Java library classes as implemented in the Oracle JRE automatically.

Notice The JCK is not a stress test. It does not benchmark the implementation's performance or throughput.

Protection Against Java Decompilers Peace of mind

Java class files are easy to reverse-engineer. The very properties that enable Java applications to run anywhere make reverse translation straightforward. There are a number of Java decompilers on the market that produce amazingly readable source code.

In contrast, reverse translation of optimized native code is a hard engineering task that cannot be automated like Java bytecode decompilation.

An obfuscator can make the decompiled code less comprehensible. However, name obfuscation may cause reflection and JNI failures, whereas extensive control flow obfuscation negatively impacts performance and may provoke a VerifyError. To make things worse, these problems only manifest themselves when the respective class is actually loaded at application run time, and thus may slip through the QA process. And reverse engineering of an equivalent C++ program passed through an optimizing compiler would still be more difficult.

Excelsior JET gives you the best of both worlds. With it, you reduce the set of class and jar files comprising your Java application to a solid binary executable before shipping it to customers or delpoying it to production servers. You avoid the obfuscation trade-offs: reduced performance and increased risk of run-time errors. You may continue using tools that encrypt strings and resources, and you may pass classes not accessed via JNI or reflection through a name obfuscator if you know what you are doing.

Excelsior JET, Enterprise Edition enables you to protect not only plain Java applications, but also Eclipse RCP applications and Tomcat Web applications. You can find more information and examples on the dedicated pages:

The most secure way to deploy Eclipse RCP apps

Protect your Web apps against decompilation and tampering

Improved User Experience Faster startup, smaller footprint, no dependencies

Notice All charts represent data gathered by running particular applications in specific environments. Your mileage will vary.

Natively precompiled Java code runs directly on hardware right from the start. The absence of the warm-up cycle and JIT compilation overhead results in faster application startup and optimal code performance.

Excelsior JET keeps the size of the Java SE runtime as small as possible, reducing the download size and disk footprint of Java applications. The unique Java Runtime Slim-Down feature enables you to selectively omit parts of the Java SE standard library that are not used by your application.

The run time memory footprint is also somewhat smaller because the Excelsior JET JVM is leaner compared to traditional implementations.

Finally, the applications precompiled with Excelsior JET do not require the JRE, and the included deployment tools help you package your optimized application together with the necessary runtime files into a naitve installer.

Featured Success Story

Read the full case study

You can read more case studies or go see for yourself. Download Your 90-days Evaluation Copy Now

Excelsior JET is available in three editions. Licenses for each platform are sold separately; discounts apply to multiplatform bundles. The licenses are perpetual and come with one year of support and upgrades.

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Excelsior JET, Professional Edition for Windows with 1 Year of Standard Support

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$X,XXX

Price is per developer seat, no runtime royalties^*
Includes one year of support and upgrades
Perpetual license, support renewal optional

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Notice New support period begins where the previous one left off.

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^* Notice The Excelsior JET Runtime License prohibits deployment to embedded systems. If you are targeting devices with dedicated functionality, check out Excelsior JET Embedded.

You can test Excelsior JET thoroughly prior to purchase. Download Your 90-days Evaluation Copy Now

Microbusiness Licensing Program

MicroISVs, early stage startups, and other very small businesses employing just a few software engineers may purchase Excelsior JET at reduced prices.

Apply Now or Learn More

Non-Commercial Use

We gladly provide Excelsior JET licenses at no cost to authors of free, non-commercial Java applications that meet a few simple qualification criteria.

Get A Free License Now

Academic Use

Temporarily unavailable.

Notice Only 64‑bit Professional and Enterprise Editions are available for OS X.

Capability ↓ Editions →	Ent	Pro	Std
Java SE 8 compatible new	✔	✔	✔
Generates 32-bit (x86) native executables	✔	✔	✔
Generates 64-bit (x64) native executables	✔	✔
Maximizes performance on a multi-core CPU	✔	✔
Maximizes performance on multi-processor servers	✔
Minimizes GC pauses on multi-core & multi-CPU systems	✔
Reduces application cold startup time	✔	✔
Protects plain Java SE and JavaFX applications from decompilers	✔	✔	✔
Protects Eclipse RCP applications	✔
Protects Tomcat Web applications	✔
Creates JRE-independent application setups	✔	✔	✔
Reduces application download size and disk footprint x86	✔	✔