GraalVM is a Java Development Kit (JDK) written in Java. The open-source distribution of GraalVM is based on OpenJDK, and the enterprise distribution is based on Oracle JDK. As well as just-in-time (JIT) compilation, GraalVM can compile a Java application ahead of time. This allows for faster initialization, greater runtime performance, and decreased resource consumption, but the resulting executable can only run on the platform it was compiled for.

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Quick Facts Developer(s), Stable release ...

GraalVM

Developer(s)	Oracle Corporation
Stable release	GraalVM for JDK 22 / 19 March 2024; 59 days ago (2024-03-19)
Repository	github.com/oracle/graal
Written in	Java
Operating system	Linux, Windows and macOS[1]
Platform	Java Virtual Machine
Type	Java dynamic compiler and runtime
License	Community Edition: GPLv2;[2][3] Oracle GraalVM: "GFTC".
Website	www.graalvm.org

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It provides additional programming languages and execution modes. The first production-ready release, GraalVM 19.0, was distributed in May 2019.^[4] The most recent release is GraalVM for JDK 22, made available in March 2024.^[5]

Major differentiators of GraalVM compared to the base JDK include:

• Graal Compiler, a just-in-time (JIT) compiler.
• GraalVM Native Image is a technology to compile Java applications ahead of time.
• Truffle Language Implementation Framework and GraalVM SDK, a Java-based framework and a collection of APIs for developing high-performance language runtimes.
• GraalVM Polyglot API, an API to embed guest language code in a Java-based host application.
• JavaScript Runtime, an ECMAScript 2023-compliant JavaScript runtime, as well as Node.js.
• LLVM Runtime is a runtime to execute languages that can be transformed into LLVM bitcode.

• To improve the performance of Java virtual machine (JVM)-based languages to match native languages.^[6][7]
• To reduce the startup time of JVM-based applications by compiling them ahead of time.
• To enable GraalVM integration into the Oracle Database, OpenJDK, Android/iOS, and similar custom embeddings.
• To enable embedding guest language code in a JVM-based host application.
• To enable mixing of code from any programming language in a single application, billed as a "polyglot application."^[6][8]

GraalVM has its roots in the Maxine Virtual Machine project at Sun Microsystems Laboratories (now Oracle Labs). The project's goal was to write a Java virtual machine in Java itself to avoid the problems of developing in C++, particularly manual memory management, and benefit from meta-circular optimizations. The project changed its focus to the compiler and to hook it into the HotSpot runtime as much as possible. The GraalVM compiler, Graal, was started by manually converting the code of the HotSpot client compiler (named "C1") into Java, replacing the previous Maxine compiler.^[9]

Graal was included in HotSpot-based JDK releases such as OpenJDK from Java SE 9 through 15, to provide experimental ahead-of-time compilation. TheUseJVMCICompiler option also enabled the use of Graal as a replacement for the server compiler (named "C2").^[10] The option was removed in Java SE 16 to eliminate the duplicate effort of maintaining a version in the JDK and a standalone GraalVM release. A similar function to create a native executable from a Java application is provided by the native-image tool of standalone GraalVM releases. The tool processes a Java application's classes and other metadata to create a binary for a specific operating system and architecture. It can be used to build a native executable or a native shared library.

GraalVM is available as Oracle GraalVM under the GraalVM Free Terms and Conditions (GFTC) license, as Oracle GraalVM Enterprise Edition accessible by accepting the "OTN License Agreement Oracle GraalVM Enterprise Edition Including License for Early Adopter Versions" [1 or as a Community Edition with an open-source license. Oracle Corporation announced the release of Oracle GraalVM Enterprise Edition on May 8, 2019, and Oracle GraalVM on June 13, 2023, introducing a new GraalVM Free Terms and Conditions (GFTC) license. GraalVM can substitute for a default JDK on Linux and macOS platforms on x64 and AArch64 CPUs, and on a Windows x64 platform. The release schedule is at the Oracle Help Center and the GraalVM website.

The GraalVM compiler, Graal, is shipped with the components of a normal Java virtual machine (OpenJDK). Additional components are included in GraalVM to enable new execution modes (GraalVM Native Image) or programming languages (LLVM runtime, GraalVM JavaScript as a potential replacement to the deprecated Nashorn engine, TRegex as a regular expression engine).

Another advantage of GraalVM is the possibility to embed code from a guest language in Java and write "polyglot" applications.^[8] A developer can integrate JavaScript, Python, or other supported languages inside Java source code, granting them the characteristic advantages of those languages. A host Java application and a guest language pass data back and forth in the same memory space. It is possible thanks to the Truffle Language Implementation Framework^[28] and the GraalVM Polyglot API. Below is the example how to call a function defined in Python from Java:

try (Context context = Context.create()) {
    Value function = context.eval("python", "lambda x: x + 1");
    assert function.canExecute();
    int x = function.execute(41).asInt();
    assert x == 42;
}

The Python function increments of a unit the value provided and then returns it to the host language. From Java, for security purposes, we ask first if the variable function can be executed via the canExecute() call, and then we invoke the function with the execute() call. Find more examples in the Embedding Languages reference documentation.

GraalVM is written in and for the Java ecosystem. It can run applications written in all languages that compile to the Java bytecode format, for example, Java, Scala, Kotlin, and more.

Based on the Truffle Language Implementation Framework, the following additional languages are designed for use with GraalVM:

• GraalJS:^[29] An ECMAScript 2023 compliant JavaScript runtime, with support for Node.js
• GraalPy:^[30] A Python 3 language implementation
• GraalVM LLVM Runtime (Sulong):^[31] An LLVM bitcode interpreter implementation
• GraalWasm:^[32][33] A WebAssembly implementation
• TruffleRuby:^[34] A Ruby language implementation with preliminary support for Ruby on Rails
• FastR:^[35] An R language implementation

Support for additional languages can be implemented by users of GraalVM. Some notable third-party language implementations are grCuda,^[36] SOMns,^[37] TruffleSqueak,^[38][39] and Yona.^[40]

GraalVM is used in various industrial scenarios:

• Disney:^[41] utilizes Native Image technology to reduce the cold-start time of some of its AWS microservices.
• Facebook:^[42] uses GraalVM to speed-up Apache Spark workloads reducing the memory footprint and the utilization of the CPU.
• Twitter:^[43] accelerates some of the microservices of the platform.
• Goldman Sachs:^[44] the international investment bank rewrote its internal programming language Slang via the Truffle framework.