问使用JUnit文件和相应的命令行工具进行基本的java 4安装需要帮助

EN

deniz@debian:~$ cd /tmp/temp2/src/com/example/example
deniz@debian:/tmp/temp2/src/com/example/example$ echo $CLASSPATH
.:/home/deniz/CLASSPATH_DIR:/usr/share/java/jogl.jar:/usr/share/java/gluegen-rt.jar:/usr/share/java/junit4.jar
deniz@debian:/tmp/temp2/src/com/example/example$ ls -l /usr/share/java/junit4.jar
lrwxrwxrwx 1 root root 16 Feb  8  2011 /usr/share/java/junit4.jar -> junit4-4.8.2.jar
deniz@debian:/tmp/temp2/src/com/example/example$ ls
MathUtils.java  MathUtilsTest.java
deniz@debian:/tmp/temp2/src/com/example/example$ javac ./*.java
deniz@debian:/tmp/temp2/src/com/example/example$ ls
MathUtils.class  MathUtils.java  MathUtilsTest.class  MathUtilsTest.java
deniz@debian:/tmp/temp2/src/com/example/example$ java MathUtils
Exception in thread "main" java.lang.NoClassDefFoundError: MathUtils (wrong name: com/example/example/MathUtils)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
    at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:334)
Could not find the main class: MathUtils. Program will exit.
deniz@debian:/tmp/temp2/src/com/example/example$ java MathUtilsTest
Exception in thread "main" java.lang.NoClassDefFoundError: MathUtilsTest (wrong name: com/example/example/MathUtilsTest)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
    at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:334)
Could not find the main class: MathUtilsTest. Program will exit.
deniz@debian:/tmp/temp2/src/com/example/example$ cat MathUtils.java
package com.example.example;

public class MathUtils
{
    public static double multiply(double a, double b)
    {
        return a * b;
    }

    public static void main(String[] args)
    {
        double num = multiply(4.0,-5.0);
        System.out.println("The number is: " + num);
    }
}
deniz@debian:/tmp/temp2/src/com/example/example$ cat MathUtilsTest.java 
package com.example.example;

import org.junit.Test;

import static org.junit.Assert.*;

public class MathUtilsTest
{
    @Test
    public void testMultiply()
    {
        double a = 5.0;
        double b = -4.0;

        double expected = -20.0;
        double result = MathUtils.multiply(a, b);

        assertEquals(expected, result, 0.00001);
    }
}
deniz@debian:/tmp/temp2/src/com/example/example$