Question

I have a class with various variables

public class myClass{

    public int id;
    public String category;
    public String description;
    public String start;
    public String end;
}

Is there a way to check, either by creating an internal function or checking from the calling object, whether or not a variable exists?

E.g. To check whether myClass contains a variable called “category” (it does). Or whether it contains a category called “foo” (it does not).

Answer 1

Your compiler usually knows that pretty well, and the runtime lets you examine loaded classes with reflection.

Object someObject = ...
Class<?> someClass = someObject.getClass();
Field someField = someClass.getField("foo");

The getField() method will throw an exception if the field can not be found.