| Name | Description | Type | Package | Framework |
| ConfigurationInterpolator | A class that handles interpolation (variable substitution) for configuration Each instance of AbstractConfiguration is associated with an | Class | org.apache.commons.configuration.interpol | Apache Commons |
| ConstantLookup | A specialized lookup implementation that allows access to constant fields of Sometimes it is necessary in a configuration file to refer to a constant | Class | org.apache.commons.configuration.interpol | Apache Commons |
| EnvironmentLookup | A specialized lookup implementation that allows access to environment This implementation relies on EnvironmentConfiguration to resolve | Class | org.apache.commons.configuration.interpol | Apache Commons |
| ExprLookup | Lookup that allows expressions to be evaluated. | Class | org.apache.commons.configuration.interpol | Apache Commons |
| ExprLookup .Variable | The key and corresponding object that will be made available to the JexlContext for use in expressions. | Class | org.apache.commons.configuration.interpol.ExprLookup | Apache Commons |
| ExprLookup .Variables | List wrapper used to allow the Variables list to be created as beans in DefaultConfigurationBuilder. | Class | org.apache.commons.configuration.interpol.ExprLookup | Apache Commons |