enum type in Java 5 and onwards for the purpose you have described. It is type safe.If you are talking about the difference between instance variable and class variable, instance variable exist per object created. While class variable has only one copy per class loader regardless of the number of objects created.
Java 5 and up enum type
public enum Color{
RED("Red"), GREEN("Green");
private Color(String color){
this.color = color;
}
private String color;
public String getColor(){
return this.color;
}
public String toString(){
return this.color;
}
}
If you wish to change the value of the enum you have created, provide a mutator method.
public enum Color{
RED("Red"), GREEN("Green");
private Color(String color){
this.color = color;
}
private String color;
public String getColor(){
return this.color;
}
public void setColor(String color){
this.color = color;
}
public String toString(){
return this.color;
}
}
Example of accessing:
public static void main(String args[]){
System.out.println(Color.RED.getColor());
// or
System.out.println(Color.GREEN);
}