JavaClass.java

// class definition
public class JavaClass {
    
    // this is a field, also known as class variable
    private String variableName;
 
    // they can also be public, but this is not recommended!
    public String badVariable;
 
    // you can initialize the value in the same step
    private String initalized = "HELLO";
 
    // you can choose any type you want
    private int number = 0;
 
    // you can also declare a variable as final
    // this means that it will never ever change
    private final int neverChange = 42;
 
    // each class needs a constructor
    // this is called when an object is made from the class
    // if you dont write any constructor, an empty one is made for you
    public JavaClass() {
      // initializing code here
    }
 
    // constructors can also take parameters
    public JavaClass(String name) {
    	variableName = name;
    }
 
    // you can have many constructors, as long as type or number of
    // arguments set them apart
    public JavaClass(String name, int newNumber) {
    	variableName = name;
    	number = newNumber;
    }
 
    // you'll want methods for your class
    // a method starts with public or private
    // followed by return type, name, parameters
    // not that this method has retun type int and 0 paramaters
    public int myMethod() {
    	return number; // because we have a return type, we have to return something
    }
 
    // this one takes one parameter and has return type void
    // void means it returns nothing
    public void thisIsVoid(String param) {
    	System.out.println(param);
    }
 
    // you will often need accessors to your fields (class variables)
    // first, we'll make it possible to get the private variable 
    // variableName
    public String getVariableName() {
        return variableName;
    }
 
    // second, we'll make it possible to set the private variable
    // variableName
    public void setVariableName(String name) {
        variableName = name;
    }
}