Processing项目启动报错：java.lang.NoClassDefFoundError: processing/core/PApplet

解决方案 #

核心问题

你的运行配置里把core.jar放到了模块路径（-p参数），但Processing的core.jar不是Java模块化JAR，JVM无法通过模块路径加载其中的类，导致找不到PApplet。

修复步骤

1. 打开Eclipse的「运行配置」（Run Configurations）
2. 找到MovingRectangle的运行配置，切换到「Arguments」标签页
3. 删除VM参数里的-p "C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\core.jar"这一行
4. 把core.jar的路径添加到Classpath参数中，修改后的Classpath应该是：

   C:\Users\user\eclipse-workspace\embodiedInteractionDance\bin;C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\core.jar;C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\gluegen-rt.jar;C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\jogl-all.jar;C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\MidPose.jar;C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\gluegen-rt-natives-windows-amd64.jar;C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\jogl-all-natives-windows-amd64.jar;C:\Users\user\eclipse-workspace\embodiedInteractionDance\libs\jogl-all-noawt-2.2.4.jar
   

5. 保存配置后重新运行

额外检查项

• 确认core.jar文件完好：打开JAR文件，检查是否存在processing/core/PApplet.class
• 重新添加构建路径：右键项目→Build Path→Add External Archives，重新选择core.jar
• 清理重建项目：点击菜单栏「Project」→「Clean」，选择当前项目后执行清理，再重新编译运行

内容的提问来源于stack exchange，提问作者KMM