Spring项目JUnit测试报错ClassNotFoundException解决、

MyEclipse项目上有红色感叹号，各包显示正常。用JUnit测试部分能运行，部分报错，报错如下：

Class not found n_jdbc.UserDaoTest
java.lang.ClassNotFoundException: n_jdbc.UserDaoTest
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClass(RemoteTestRunner.java:693)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClasses(RemoteTestRunner.java:429)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:452)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

解决：

在Window----->Preferences下---->Java---->Compiler---->Building 页面 :

修改如下两项属性：error---->Warning

修改后为：

再次运行正常，原因还没弄明白。

 有问题在Problem中查找