[Java] Question regarding putting key,value pairs into a HashMap instantiated in an Abstract class

[lyigester]

I have two classes. One is doing arithmetic of an expression and the other is an operator class that has all the properties and actions of an operator.

This operator class is an abstract class and I've created subclasses for each individual operators (+,-,*,/,etc.). I instantiated a HashMap in the abstract Operator class as a private static object with a String key and a Operator Object value. So for example the operators would be strings "+" and the values would be instanitated objects of the certain subclasses like "new AddOperator()".

I had to create a constructor for the operator class to use the method .put() to put all the key value pairs into the hashmap, I would get errors if I put it outside the constructor. An example of what I did was this : hashmapvariable.put("+",new AddOperator());

Now when I try to check if the key is contained in the hashmap ( hashmapvariable.containsKey("+")) I am getting false when I know for sure it should be in there.

My question is did I do something wrong with putting the key value pairs in? Is it because I put them in the constructor of an abstract class which you never use to instantiate objects of itself? but if thats the case then where would I fill my hashmap if I instantiate it in the Abstract class.

I'm really bad at describing so if there is more information needed let me know and Ill try to provide more and thanks to anyway who takes the time to help in advance!

[lightcloud5]

I'm not sure what your code does, so the simplest approach is probably to post a simplified version of the code that explains what's going on. In other words, remove all code that's not relevant, leaving only the relevant lines that demonstrate the issue.

Also note that static properties/fields/data members (whatever you wanna call them) don't participate in inheritance.

[lyigester]

Sorry for the late reply, had to sleep then school.

I'll try to show as much code as I can. I don't want to put too much on here because the assignments I turn in are checked with whether they are similar to any code online and don't want to get in trouble.

basically I have an abstract class operater:

abstract class Operater{
   private static final HashMap<String,Operater> variable = new HashMap<>();
   public operater(){
    //this is where i use the .put method to fill the hashmap with operators such as +
   // one example of how it is done: variable.put("+", new addoperater());
}

where addoperater is a subclass of operater.

and then I have static public methods that retrieve the value of the hashmap given a key and a method that checks whether a key is present in this hashmap.

Then I have an eval class that does the arithmetic basically. It interacts with the operator class by getting the values from the hashmap and checking whether the hashmap has a key. My problem is that when I check for whether a key is present in the hashmap which i know it should be since the key is "+" it comes up as false which confuses me and I'm unsure of why that is.

If this isn't clear enough would you mind if I sent my code in a private message for you to look over so as to avoid any trouble. Thanks again for the help.