这两天编译Spring5.2的源码，把人搞的头大，其中编译spring-core时，报错如下：
Error:Kotlin: [Internal Error] java.lang.LinkageError: loader constraint violation: loader (instance of org/jetbrains/kotlin/cli/jvm/plugins/PluginURLClassLoader$SelfThenParentURLClassLoader) previously initiated loading for a different type with name "kotlin/sequences/Sequence" at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:763) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) at java.net.URLClassLoader.access$100(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:368) at java.net.URLClassLoader$1.run(URLClassLoader.java:362) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:361) at org.jetbrains.kotlin.cli.jvm.plugins.PluginURLClassLoader$SelfThenParentURLClassLoader.findClass(PluginURLClassLoader.kt:47) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:763) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) at java.net.URLClassLoader.access$100(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:368) at java.net.URLClassLoader$1.run(URLClassLoader.java:362) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:361) at org.jetbrains.kotlin.cli.jvm.plugins.PluginURLClassLoader$SelfThenParentURLClassLoader.findClass(PluginURLClassLoader.kt:47) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at kotlin.coroutines.experimental.SequenceBuilderKt__SequenceBuilderKt.buildSequence(SequenceBuilder.kt:24) at org.jetbrains.kotlin.scripting.compiler.plugin.ScriptiDefinitionsFromClasspathDiscoverySourceKt.discoverScriptTemplatesInClasspath(ScriptiDefinitionsFromClasspathDiscoverySource.kt:53) at org.jetbrains.kotlin.scripting.compiler.plugin.ScriptDefinitionsFromClasspathDiscoverySource.<init>(ScriptiDefinitionsFromClasspathDiscoverySource.kt:37) at org.jetbrains.kotlin.scripting.compiler.plugin.ScriptingCompilerConfigurationExtension.updateConfiguration(ScriptingCompilerConfigurationExtension.kt:56) at org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment.<init>(KotlinCoreEnvironment.kt:201) at org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment.<init>(KotlinCoreEnvironment.kt:120) at org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment$Companion.createForProduction(KotlinCoreEnvironment.kt:433) at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.createCoreEnvironment(K2JVMCompiler.kt:295) at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:147) at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:51) at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:95) at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:50) at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:88) at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$1.invoke(CompileServiceImpl.kt:399) at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$1.invoke(CompileServiceImpl.kt:98) at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:927) at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:98) at org.jetbrains.kotlin.daemon.common.DummyProfiler.withMeasure(PerfUtils.kt:137) at org.jetbrains.kotlin.daemon.CompileServiceImpl.checkedCompile(CompileServiceImpl.kt:957) at org.jetbrains.kotlin.daemon.CompileServiceImpl.doCompile(CompileServiceImpl.kt:926) at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:397) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357) at sun.rmi.transport.Transport$1.run(Transport.java:200) at sun.rmi.transport.Transport$1.run(Transport.java:197) at java.security.AccessController.doPrivileged(Native Method) at sun.rmi.transport.Transport.serviceCall(Transport.java:196) at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:834) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688) at java.security.AccessController.doPrivileged(Native Method) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)
百度上基本上搜不出什么有用的解决方法，唯一一个还是让我升级idea的版本。我去，这个就算了吧，后来在google上搜，发现是idea中kotlin插件的版本太低引起的，因为spring-core这项目好像用到了kotlin。于是我就开始尝试升级kotlin插件，但是在idea的插件管理中，找到kotlin，居然没有更新按钮！继续google，终于找到位置，如下：
settings -> Languages & Frameworks -> kotlin
这个界面中会显示当前kotlin版本，和可下载的最新版本，我这里下载1.3.50版本后重启idea后spring源码终于编译成功！！
整整4天啊，真是不容易，其中踩了各种坑。