How do you add classes to a main method

Question

I have three .java files and I need to get them to work together. I think that I need to add all the classes to a main method but I am not sure if this is correct and if I just add the name of the class and the format.

I figured it out, the three files had a package listed at the top of each. I created a new Java project in Eclipse and then a source folder and in the source folder I created a package with the name that they all referenced. Now it runs. Thanks for all of you help for the Eclipse/Java beginner.

Answer 1

You are right: what you think is not right :P

Java can find the classes that you need, you can just use them straight away. I get the feeling that you come from a C/C++ background (like me) and hence think that you will need to "include" the other classes.

java uses the concept of namespaces and classpaths to find classes. Google around for it.

A little example of how variety of classes can be used together:

// A.java

public class A {
    public void sayIt() { sysout("Said it by A!"); }
}

// B.java
public class B {
    public void doIt() { sysout("Done it by B!"); }
}

// MainClass.java

public class MainClass {
    public static void main(String[] args) {
         A aObj = new A();
         B bObj = new B();

         aObj.sayIt();
         bObj.doIt();
    }
}

Note that there are no includes/imports here because all of the classes are in the same namespace. If they were not, then you'd need to import them. I will not add a contrived example for that coz its too much to type, but should google for it. Info should be easy enough to find.

Cheers,
jrh