A Crash Course in Java Redirected from Bachelor/Year 2/Object Oriented Modelling/Summary/Page Title

"Hello, World!" in Java

public class Greeter{

   private String name;

   public Greeter(String aName){
      name = aName;
   } 

   public String sayHello(){
      return "Hello, " + name + "!";
   }
}

constructor: Greeter(String aName)
method: sayHello()
field: private String name

public class GreeterTester
{
   public static void main(String[] args)
   {
      Greeter worldGreeter = new Greeter("World");
      String greeting = worldGreeter.sayHello();
      System.out.println(greeting);
   }
}

this class contains a main method, which means its runnable.
static: it doesn't operate on objects.
args: command-line arguments

If you want to run your program in a Shell Window:
    go to your folder of your program,
    javac filename.java => Run compiles
    java filename => Start interpreter
    output...

Documentation comments

/**
   A class for producing simple greetings.
*/
 
public class Greeter {
   /**
      Constructs a Greeter object that can greet a person or 
      entity.
      @param aName the name of the person or entity who should
      be addressed in the greetings.
   */
   public Greeter(String aName) {
      name = aName;
   }
 
   /**
      Greet with a "Hello" message.
      @return a message containing "Hello" and the name of
      the greeted person or entity.
   */
   public String sayHello() {
      return "Hello, " + name + "!";
   }
 
   private String name;
}

Primitive Types

Object References

Parameter Passing

Packages

Basic Exception Handling

Strings

Reading Input

ArrayLists and Linked Lists

Arrays

Static Fields and Methods

Programming Style