听说Oracle 发布了一个全栈虚拟机 GraalVM，支持 Python！

Posted 2021-04-30 Java开发高级进阶

GraalVM是一个通用虚拟机，用于运行用javascript，Python 3，Ruby，R，基于JVM的语言（如Java，Scala，Kotlin和基于LLVM的语言，如C和C ++）编写的应用程序。

GraalVM消除了编程语言之间的隔离，并在共享运行时中实现了互操作性。它既可以独立运行，也可以在OpenJDK，Node.js，Oracle数据库或mysql环境中运行。

为何选择GraalVM？

GraalVM消除了编程语言之间的隔离，并在共享运行时启用了互操作性。它可以独立运行，也可以在OpenJDK，Node.js，Oracle数据库或MySQL环境中运行。

有几个因素可能会让你想要从常规的JRE切换到GraalVM：

• 其中之一可能是它声称的改进的性能

• 另一个可能是多语言功能，以透明地混合匹配支持的语言

• 还有，通过本地支持，可以将Java应用作为本机代码提供

当然，GraalVM的发布，也吸引了许多技术极客的目光，想要一探究竟。本文来自国外的一名超过15年经验的软件架构师Nicolas Fränkel，看看他眼中的GraalVM。

GraalVM架构

该架构与传统的Java JDK 9之前的版本相似。

因此，GraalVM可以成为任何标准JDK的替代品。

运行java -version将返回以下的输出：

java version "1.8.0_161"Java(TM) SE Runtime Environment (build 1.8.0_161-b12)GraalVM 1.0.0-rc1 (build 25.71-b01-internal-jvmci-0.42, mixed mode)

截至目前，GraalVM仅限于Java 8功能。

一些性能测试基准

下一步是检查性能是否有所改善。我使用了JMH框架：它专注于此。

我使用了下面的代码：

并使用java -jar target / benchmarks.jar命令行在3个不同的JRE上进行了测试。

GraalVM结果

# JMH version: 1.20# VM version: JDK 1.8.0_161, VM 25.71-b01-internal-jvmci-0.42# VM invoker: /usr/local/graalvm-1.0.0-rc1/Contents/Home/jre/bin/java# VM options: <none># Warmup: 20 iterations, 1 s each# Measurement: 20 iterations, 1 s each# Timeout: 10 min per iteration# Threads: 1 thread, will synchronize iterations# Benchmark mode: Throughput, ops/time# Benchmark: ch.frankel.blog.MyBenchmark.testMethodResult "ch.frankel.blog.MyBenchmark.testMethod": 6.795 ±(99.9%) 0.016 ops/s [Average] (min, avg, max) = (6.477, 6.795, 6.967), stdev = 0.068 CI (99.9%): [6.778, 6.811] (assumes normal distribution)# Run complete. Total time: 00:06:59Benchmark Mode Cnt Score Error UnitsMyBenchmark.testMethod thrpt 200 6.795 ± 0.016 ops/s

Oracle JDK 8结果

# JMH version: 1.20# VM version: JDK 1.8.0_92, VM 25.92-b14# VM invoker: /Library/Java/JavaVirtualMachines/jdk1.8.0_92.jdk/Contents/Home/jre/bin/java# VM options: <none># Warmup: 20 iterations, 1 s each# Measurement: 20 iterations, 1 s each# Timeout: 10 min per iteration# Threads: 1 thread, will synchronize iterations# Benchmark mode: Throughput, ops/time# Benchmark: ch.frankel.blog.MyBenchmark.testMethodResult "ch.frankel.blog.MyBenchmark.testMethod": 6.727 ±(99.9%) 0.017 ops/s [Average] (min, avg, max) = (6.466, 6.727, 6.899), stdev = 0.070 CI (99.9%): [6.710, 6.743] (assumes normal distribution)# Run complete. Total time: 00:07:00Benchmark Mode Cnt Score Error UnitsMyBenchmark.testMethod thrpt 200 6.727 ± 0.017 ops/s

Oracle JDK 9结果

# JMH version: 1.20# VM version: JDK 9.0.4, VM 9.0.4+11# VM invoker: /Library/Java/JavaVirtualMachines/jdk-9.0.4.jdk/Contents/Home/bin/java# VM options: <none># Warmup: 20 iterations, 1 s each# Measurement: 20 iterations, 1 s each# Timeout: 10 min per iteration# Threads: 1 thread, will synchronize iterations# Benchmark mode: Throughput, ops/time# Benchmark: ch.frankel.blog.MyBenchmark.testMethodResult "ch.frankel.blog.MyBenchmark.testMethod": 7,136 ±(99.9%) 0,026 ops/s [Average] (min, avg, max) = (6,464, 7,136, 7,443), stdev = 0,111 CI (99.9%): [7,110, 7,162] (assumes normal distribution)# Run complete. Total time: 00:07:26Benchmark Mode Cnt Score Error UnitsMyBenchmark.testMethod thrpt 200 7,136 ± 0,026 ops/s

测试比较如下：

性能方面，GraalVM和Java 8之间的差距并不明显，而他们和Java 9之间标准差最高。

本地化

GraalVM能够通过native-image命令行将JAR转换为本机可执行文件。我试图用创建的JAR来完成它。

native-image -H:+JNI -jar target/benchmarks.jar

但是，当试图运行新创建的二进制文件时，我偶然发现了以下内容：

Exception in thread "main" java.lang.reflect.InvocationTargetException at java.lang.Throwable.<init>(Throwable.java:310) at java.lang.Exception.<init>(Exception.java:102) at java.lang.ReflectiveOperationException.<init>(ReflectiveOperationException.java:89) at java.lang.reflect.InvocationTargetException.<init>(InvocationTargetException.java:72) at com.oracle.svm.reflect.proxies.Proxy_3_Main_main.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Method.java:498) at com.oracle.svm.core.JavaMainWrapper.run(JavaMainWrapper.java:199) at Lcom/oracle/svm/core/code/CEntryPointCallStubs; .com_002eoracle_002esvm_002ecore_002eJavaMainWrapper_002erun_0028int_002corg_002egraalvm_002enativeimage_002ec_002etype_002eCCharPointerPointer_0029(generated:0)Caused by: java.lang.IllegalArgumentException: class org.openjdk.jmh.runner.options.TimeValue is not a value type at java.lang.Throwable.<init>(Throwable.java:265) at java.lang.Exception.<init>(Exception.java:66) at java.lang.RuntimeException.<init>(RuntimeException.java:62) at java.lang.IllegalArgumentException.<init>(IllegalArgumentException.java:52) at joptsimple.internal.Reflection.findConverter(Reflection.java:66) at joptsimple.ArgumentAcceptingOptionSpec.ofType(ArgumentAcceptingOptionSpec.java:106) at org.openjdk.jmh.runner.options.CommandLineOptions.<init>(CommandLineOptions.java:109) at org.openjdk.jmh.Main.main(Main.java:41) ... 4 more

更糟的是，试图为Spring Pet Clinic创建一个镜像失败，原因如下：

error: unsupported features in 3 methodsDetailed message:Error: com.oracle.graal.pointsto.constraints.UnsupportedFeatureException: Unsupported constructor java.lang.ClassLoader.<init>(ClassLoader) is reachable: The declaring class of this element has been substituted, but this element is not present in the substitution classTo diagnose the issue, you can add the option -H:+ReportUnsupportedElementsAtRuntime.The unsupported element is then reported at run time when it is accessed the first time.Trace: at parsing java.security.SecureClassLoader.<init>(SecureClassLoader.java:76)Call path from entry point to java.security.SecureClassLoader.<init>(ClassLoader): at java.security.SecureClassLoader.<init>(SecureClassLoader.java:76) at java.net.URLClassLoader.<init>(URLClassLoader.java:100) at org.springframework.boot.loader.LaunchedURLClassLoader.<init>(LaunchedURLClassLoader.java:50) at org.springframework.boot.loader.Launcher.createClassLoader(Launcher.java:74) at org.springframework.boot.loader.Launcher.createClassLoader(Launcher.java:64) at org.springframework.boot.loader.Launcher.launch(Launcher.java:49) at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) at com.oracle.svm.reflect.proxies.Proxy_1_JarLauncher_main.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Method.java:498) at com.oracle.svm.core.JavaMainWrapper.run(JavaMainWrapper.java:199) at Lcom/oracle/svm/core/code/CEntryPointCallStubs; .com_002eoracle_002esvm_002ecore_002eJavaMainWrapper_002erun_0028int_002corg_002egraalvm_002enativeimage_002ec_002etype_002eCCharPointerPointer_0029(generated:0)Error: com.oracle.graal.pointsto.constraints.UnsupportedFeatureException: Unsupported field java.net.URL.handlers is reachableTo diagnose the issue, you can add the option -H:+ReportUnsupportedElementsAtRuntime. The unsupported element is then reported at run time when it is accessed the first time.Trace: at parsing java.net.URL.setURLStreamHandlerFactory(URL.java:1118)Call path from entry point to java.net.URL.setURLStreamHandlerFactory(URLStreamHandlerFactory): at java.net.URL.setURLStreamHandlerFactory(URL.java:1110) at org.springframework.boot.loader.jar.JarFile.resetCachedUrlHandlers(JarFile.java:383) at org.springframework.boot.loader.jar.JarFile.registerUrlProtocolHandler(JarFile.java:373) at org.springframework.boot.loader.Launcher.launch(Launcher.java:48) at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) at com.oracle.svm.reflect.proxies.Proxy_1_JarLauncher_main.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Method.java:498) at com.oracle.svm.core.JavaMainWrapper.run(JavaMainWrapper.java:199) at Lcom/oracle/svm/core/code/CEntryPointCallStubs; .com_002eoracle_002esvm_002ecore_002eJavaMainWrapper_002erun_0028int_002corg_002egraalvm_002enativeimage_002ec_002etype_002eCCharPointerPointer_0029(generated:0)Error: com.oracle.graal.pointsto.constraints.UnsupportedFeatureException: Unsupported method java.security.ProtectionDomain.getCodeSource() is reachable: The declaring class of this element has been substituted, but this element is not present in the substitution classTo diagnose the issue, you can add the option -H:+ReportUnsupportedElementsAtRuntime. The unsupported element is then reported at run time when it is accessed the first time.Trace: at parsing org.springframework.boot.loader.Launcher.createArchive(Launcher.java:118)Call path from entry point to org.springframework.boot.loader.Launcher.createArchive(): at org.springframework.boot.loader.Launcher.createArchive(Launcher.java:117) at org.springframework.boot.loader.ExecutableArchiveLauncher.<init>(ExecutableArchiveLauncher.java:38) at org.springframework.boot.loader.JarLauncher.<init>(JarLauncher.java:35) at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) at com.oracle.svm.reflect.proxies.Proxy_1_JarLauncher_main.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Method.java:498) at com.oracle.svm.core.JavaMainWrapper.run(JavaMainWrapper.java:199) at Lcom/oracle/svm/core/code/CEntryPointCallStubs; .com_002eoracle_002esvm_002ecore_002eJavaMainWrapper_002erun_0028int_002corg_002egraalvm_002enativeimage_002ec_002etype_002eCCharPointerPointer_0029(generated:0)Error: Processing image build request failed

动态类加载不适用于GraalVM。我尝试使用H2和HSQLDB独立JAR ......无济于事。在这两种情况下，我得到了以下堆栈：

java.lang.NullPointerException at com.oracle.graal.pointsto.ObjectScanner.scanField(ObjectScanner.java:113) at com.oracle.graal.pointsto.ObjectScanner.doScan(ObjectScanner.java:263) at com.oracle.graal.pointsto.ObjectScanner.finish(ObjectScanner.java:307) at com.oracle.graal.pointsto.ObjectScanner.scanBootImageHeapRoots(ObjectScanner.java:78) at com.oracle.graal.pointsto.ObjectScanner.scanBootImageHeapRoots(ObjectScanner.java:60) at com.oracle.graal.pointsto.BigBang.checkObjectGraph(BigBang.java:581) at com.oracle.graal.pointsto.BigBang.finish(BigBang.java:552) at com.oracle.svm.hosted.NativeImageGenerator.doRun(NativeImageGenerator.java:653) at com.oracle.svm.hosted.NativeImageGenerator.lambda$run$0(NativeImageGenerator.java:381) at java.util.concurrent.ForkJoinTask$AdaptedRunnableAction.exec(ForkJoinTask.java:1386) at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289) at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056) at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692) at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)----

结论

GraalVM具有许多有前景远大的功能，包括多语言功能，尽管我现在对该功能没什么兴趣。但是，从我有限的测试后，它仍然有改善的余地。在性能方面，Java 9表现更出色。

本文摘自官网和云智时代