JUnit显示erro java.lang.NoClassDefFoundError:org/JUnit/runner/manipulation/Filter

这是我在运行JUnit 4.jar文件库时遇到的错误，我已将JUnit 4.jar文件库放置在buildpath中。我可以从JUnit jar文件访问所有函数，但是当我运行JUnit测试时，我在控制台中得到失败错误和此消息

您应该尝试“添加库”，然后选择JUnit，而不是直接添加jar！ 祝你好运：）

可能的副本

# Junit not working giving error #

Tried testing basic add operation using Junit its showing this error on my mac

# AddTest.java #

    import static org.junit.Assert.*;

    import org.junit.Test;

        public class AddTest {

    @Test
    public void Addtest() {

        MyJUnitClass junit = new MyJUnitClass();

        int result = junit.add(100, 200);
        assertEquals(300, result);
       } 

        }

# MyJunitClass #
    public class MyJUnitClass {
    public int add(int a, int b) {
        return a+b;
    }

    public String conCat(String a, String b) {
        return a+b;
    }
        }



java.lang.NoClassDefFoundError: org/junit/runner/manipulation/Filter
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:332)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadTestLoaderClass(RemoteTestRunner.java:380)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createRawTestLoader(RemoteTestRunner.java:370)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createLoader(RemoteTestRunner.java:365)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.defaultInit(RemoteTestRunner.java:309)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.init(RemoteTestRunner.java:224)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:208)
Caused by: java.lang.ClassNotFoundException: org.junit.runner.manipulation.Filter
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 8 more