javac 错误：“import x” 中的“package x 不存在”

我正在尝试使用以下命令使用命令提示符编译我的java文件“ check4PrimeTest.java”：

javac -classpath .：junit.jar check4PrimeTest.java

我收到以下错误：

错误： package junit.framework 不存在 import junit.framework.*;

我不确定为什么我会得到这个错误，因为我在我的程序中导入了junit.framework.*。

下面是我的代码：

package check4prime;
// check4PrimeTest.java

//Imports 
import junit.framework.*;

public class check4PrimeTest extends TestCase {

    //Initialize a class to work with. 
    private check4Prime check4prime = new check4Prime();

    //constructor 
    public check4PrimeTest (String name) { 
        super(name);
    }

    //Main entry point 
    public static void main(String[] args) {
        System.out.println("Starting test...");
        junit.textui.TestRunner.run(suite());
        System.out.println("Test finished...");
    } // end main() 

    //Test case 1 
    public void testCheckPrime_true() {
        assertTrue(check4prime.primeCheck(3));
    }

    //Test cases 2,3 
    public void testCheckPrime_false() {
        assertFalse(check4prime.primeCheck(0));
        assertFalse(check4prime.primeCheck(1000));
    }

    //Test case 7 
    public void testCheck4Prime_checkArgs_char_input() { 
        try {
            String [] args= new String[1];
            args[0]="r";
            check4prime.checkArgs(args);
            fail("Should raise an Exception.");
        } catch (Exception success) { 
            //successful test
        }
    } //end testCheck4Prime_checkArgs_char_input() 

    //Test case 5 
    public void testCheck4Prime_checkArgs_above_upper_bound() {
        try { 
            String [] args= new String[1];
            args[0]="10001";
            check4prime.checkArgs(args);
            fail("Should raise an Exception.");
        } catch (Exception success) { 
            //successful test
        }
    } // end testCheck4Prime_checkArgs_upper_bound() 

    //Test case 4 
    public void testCheck4Prime_checkArgs_neg_input() {
        try { 
            String [] args= new String[1];
            args[0]="-1";
            check4prime.checkArgs(args);
            fail("Should raise an Exception.");
        } catch (Exception success) { 
            //successful test
        }
    } // end testCheck4Prime_checkArgs_neg_input()

    //Test case 6
    public void testCheck4Prime_checkArgs_2_inputs() {
        try { 
            String [] args= new String[2];
            args[0]="5";
            args[1]="99";
            check4prime.checkArgs(args);
            fail("Should raise an Exception.");
         } catch (Exception success) {
            //successful test 
         } 
    } // end testCheck4Prime_checkArgs_2_inputs 

    //Test case 8 
    public void testCheck4Prime_checkArgs_0_inputs() {
        try { 
            String [] args= new String[0];
            check4prime.checkArgs(args);
            fail("Should raise an Exception.");
        } catch (Exception success) { 
            //successful test
        } 
    } // end testCheck4Prime_checkArgs_0_inputs 

    //JUnit required method. 
    public static Test suite() { 
        TestSuite suite = new TestSuite(check4PrimeTest.class);
        return suite;
    } //end suite() 

} //end check4PrimeTest