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java - What is the best way to know if all the variables in a Class are null?

This would mean that the class was initialized, but the variables were not set.

A sample Class:

public class User {

    String id = null;
    String name = null;

    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

The actual class is huge that I prefer not to check if(xyz == null) for each of the variables.

question from:https://stackoverflow.com/questions/12362212/what-is-the-best-way-to-know-if-all-the-variables-in-a-class-are-null

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1 Answer

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by (71.8m points)

Try something like this:

public boolean checkNull() throws IllegalAccessException {
    for (Field f : getClass().getDeclaredFields())
        if (f.get(this) != null)
            return false;
    return true;            
}

Although it would probably be better to check each variable if at all feasible.


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