Junit test from commandline No runnable method exception

TestJunit class

import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class TestJunit 
{
   @Test
   public void testAdd() 
   {
      String str= "Junit is working fine";
      assertEquals("Junit is working fine",str);
   }
}

TestRunner class
/********************************************/
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;

    public class TestRunner {
       public static void main(String[] args) {
          Result result = JUnitCore.runClasses(TestJunit.class);
          for (Failure failure : result.getFailures()) {
             System.out.println(failure.toString());
          }
          System.out.println(result.wasSuccessful());
       }
    }

I used javac -cp /root/Documents/unit\ tests/junit-4.10.jar TestJunit.java TestRunner.java

to compile and java -cp /root/Documents/unit\ tests/junit-4.10.jar:. org.junit.runner.JUnitCore TestRunner

to run. It compiles without errors. But the tests fail with an exception. My test methods are annotated with @Test. Why do I get this error?