Eclipse 项目构建未能为 jre/lib/jrt-fs.jar 初始化 ct.sym

Question

This has been a nightmare lately to setup Eclipse 2020 for some demo servlet.

The project structure is:

The demo servlet dies with "Http Status 500 - Error instantiating servlet class" with the root cause as "java.lang.ClassNotFoundException".

There is a red cross beside my project and an error log stating:

Failed to init ct.sym for C:\\Users\\Pratyay Mukherjee\\AppData\\Local\\Temp\\eoi8BAC.tmp\\plugins\\org.eclipse.justj.openjdk.hotspot.jre.minimal.stripped.win32.x86_64_14.0.2.v20200815-0932\\jre\\lib\\jrt-fs.jar

I have tried rebuilding the project again and again as that is the solution for everything wrong with Eclipse. What is going wrong in my project and how can I get the servlet to work without errors?

Answer 1

The following fixed the issue for me.

• Installed OpenJDK 15.0.1 on my computer.
• In Window/Preferences/Java/Installed JREs, I added a link to the new Java version (and named it "openjdk-15" to help identify it). I unchecked the existing jre and selected the newly installed.
• I started a NEW PROJECT, and for the JRE, made sure to select the new default jre.
• I copied over the source code of the failing project into the new project.

See https://www.eclipse.org/forums/index.php/t/1106241/

Answer 2

如果有人对 Eclipse 中的 java.lang.ClassNotFoundException 感到沮丧， 这篇文章可能会有很大帮助。