RosettaCodeData/Task/Add-a-variable-to-a-class-instance-at-runtime/Groovy/add-a-variable-to-a-class-instance-at-runtime-1.groovy

class A {
    final x = { it + 25 }
    private map = new HashMap()
    Object get(String key) { map[key] }
    void set(String key, Object value) { map[key] = value }
}