How to Retrieve an Attribute by Name in Java Using Reflection?

How can I retrieve an attribute from an object in Java given its name as a string?

String attributeName = "myAttribute"; getAttributeByName(myObject, attributeName);

In Java, you can dynamically access an object's attribute (field) using reflection. This allows you to query fields by their names in string format, which is particularly useful in scenarios involving serialization, framework development, or when working with dynamic objects.

import java.lang.reflect.Field;

public class ReflectionUtil {
    public static Object getAttributeByName(Object obj, String attributeName) throws NoSuchFieldException, IllegalAccessException {
        Field field = obj.getClass().getDeclaredField(attributeName);
        field.setAccessible(true); // Allows access to private fields
        return field.get(obj);
    }
}

Causes

• The attribute name is specified as a string, making it necessary to use reflection to access it dynamically.
• Reflection allows accessing private members of classes, enabling manipulation of attributes that may not be accessible directly.

Solutions

• Use `Field` class from `java.lang.reflect` to get the attribute by name.
• Handle any potential exceptions, including `NoSuchFieldException` or `IllegalAccessException`.

Mistake: Not handling exceptions properly when accessing fields.

Solution: Use try-catch to handle `NoSuchFieldException` and `IllegalAccessException`.

Mistake: Forgetting to call `setAccessible(true)` for private fields.

Solution: Always set the field's accessibility to true before trying to access its value.