public List<ExternalReferencedHolder> getExternalReferencedHolders() {
        return Collections.unmodifiableList(new ArrayList<>(externalReferencedHolders));
    }
Attributes that are common across all the Siddhi Apps

@return Attribute Map&lt;String, Object&gt;
modules/siddhi-core/src/main/java/io/siddhi/core/config/SiddhiAppContext.java