Calling a method into a tester

[Zachary T. Anderson]

Here is a problems I am having:

public Grade getLowestGrade()  
          {  
             if (scores.size() == 0)   
                return null;  
             Grade lowestGrade = scores.get(0);  
             for (int i = 1; i < scores.size(); i++)   
             {  
                    if(scores.get(i).equals(lowestGrade))  
                    lowestGrade = scores.get(i);  
                }  
             return lowestGrade;  
          }

I have three classes: Student, Grade, and StudentTester. This code is in Student. It is calling the scores array from Student. I think this works.
What I would like to do is call the getLowestGrade method into my StudentTester, but keep getting the error:

Student.getLowestGrade();

error:
StudentTester.java:34: error: non-static method getLowestGrade() cannot be referenced from a static context  
                Student.getLowestGrade();  
                          ^  
    1 error

[Jeff Verdegan]

When you call Student.getLowestGrade(), which Student object is that supposed to operate on? Presumably there could be many students, right?

class Foo {
  public bar() {}
  public static baz() {}
}

...

Foo.bar(); // illegal -- we need an instance to call instance (non-static) methods
Foo.baz(); // correct

Foo foo = new Foo();
foo.bar(); // correct way to call an instance method
foo.baz(); // legal, but poor form

[Zachary T. Anderson]

You are my hero today..... Thank you so much. I can see what I have been doing wrong....