Titles says it all.
public class ClassA
{
public static void doStuff()
{}
public void doStuffOnObject()
{}
}
public class ClassB
{
public void main()
{
// Invoke static class method:
ClassA.doStuff();
// Invoke method belonging to instance of ClassA:
ClassA myClassA_Object = new ClassA();
myClassA_Object.doStuffOnObject();
}
}