How can i write the following statements in Java ???

Hi Everyone,
I'm studying UML and according to my textbook, it says if 2 classes have the following relationship then it can be said that there's an association relationship between those 2 classesl.
Class A and B are associated if :
- an object of class A sends a message to an object of class B
- an object of class A creates an object of class B
- an object of class A has an attribute whose value are objects of class B or collections of objects of class B
- an object of class A receives a message with an object of class B as an argument.
However, I dunno how to write those stuff into Java codes. Can someone please kindly write Java codes for those sentences ?? Thanks everyone in advance.

Sorry guys. I know I shouldn't have asked in the first place without giving it a try first. Yeah, I been doing
Java without understanding the concept of real OOP and its terms.
- an object of class A sends a message to an object of class B // ?????
- an object of class A creates an object of class B // A obj=new A();
- an object of class A has an attribute whose value are objects of class B or collections of objects of class B // A varB;
- an object of class A receives a message with an object of class B as an argument. // ?????
I get confused with the very first line and the last line . I dunno what it means by sending a message but according to what JoachimSauer mentioned
it's "calling a method" but does that mean even I called an object of the same class within , can i still refers it as sending a message ?? Like what if
i call a static method of the calling object because I dun think i create an object when I call a static method ?
Let's say
class ExampleOne
     public ExampleOne()
          ExampleOne egOne=new ExampleOne();
          egOne.display(); //can i refer to this as egOne object sending a message to an object of itself so the receiver is also egOne ??
     public void displayOne()
          System.out.println("Just an exampleOne");
class ExampleTwo
     public ExampleTwo()
          ExampleTwo.display(); // here no object creation occurs , just ExampleTwo class sends a message to itself so there's no association i assume .
     public static void displayTwo()
          System.out.println("Just an exampleTwo");
public class Main
     public static void main(String args[])
          ExampleOne exampleOne=new ExampleOne();
          ExampleTwo exampleTwo=new ExampleTwo();
}I'm confused. at first , i thought sending a message means passing values as parameters when we call a function and receiving a message means the function
being called receive values as parameters. Phew, please help me out of this.

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