问题现象：最近想更深入的研究下jmeter5.4.1的原理及功能具体实现，从官网down了个源码，在本地使用IDEA工具导入项目、编译时，报以下错误：

class jdk.internal.loader.ClassLoaders$PlatformClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$PlatformClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')
class jdk.internal.loader.ClassLoaders$PlatformClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$PlatformClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')

Gradle's dependency cache may be corrupt (this sometimes occurs after a network connection timeout.)

Re-download dependencies and sync project (requires network)
The state of a Gradle build process (daemon) may be corrupt. Stopping all Gradle daemons may solve this problem.

Stop Gradle build processes (requires restart)
Your project may be using a third-party plugin which is not compatible with the other plugins in the project or the version of Gradle requested by the project.

In the case of corrupt Gradle processes, you can also try closing the IDE and then killing all Java processes.

最后经过多轮尝试解决，解决办法如下（仅供参考）：

1、更换JDK版本。JDK11 更换为JDK8(具体版本1.8.0_291）

2、GRADLE版本及IDEA中配置。

1）GRADLE版本：

 注：最初使用GRADLE7.6版本，发现还报错。重新下载了新版本8.1.1，然后没问题了。

2）IDEA中配置GRADLE配置。