| Interface | Description | 
|---|---|
| Executor | Simple execution/work interface which can be used for internal tasks
 which need to have a full working implementation. | 
| Executor.LoggedWork<X> | |
| Executor.SqlWork | Work SPI to perform actions related to
  statelesssessions. | 
| Executor.StatefulWork | In the case of a stateful work order, the bean itself needs to be
 associated with the sessionHandler and thread rather than the word
 instance itself. | 
| Executor.Work<X> | Work SPI to perform actions within the server as if they were fully
 wrapped in our service logic. | 
| ReadOnlyStatus.IsAware | Implemented by classes that can report if a given read-only status would cause them to be in read-only mode. | 
| Class | Description | 
|---|---|
| BeanHelper | Helper for all bean implementations. | 
| BeanInstantiationGuard | Prevents creation of Spring beans based on read-only status. | 
| BeanInstantiationSubstituter | Adjusts instantiation class of Spring beans based on read-only status. | 
| BioFormatsConfigInit | Propagate the server's Bio-Formats version metadata into corresponding keys
 in the configuration service. | 
| DBEnumCheck | Hook run by the context to guarantee that various enumerations are up to
 date. | 
| DBMappedEnumCheck | When a new version of the OMERO server starts up check that the database
 includes an enumeration instance for every value mapped for code generation. | 
| DBPatchCheck | Hook run by the context. | 
| DBUnicodeUnitsCheck | Checks that the database contains correctly encoded enumerations for units of measure. | 
| DBUserCheck | Hook run by the context. | 
| EnsureEnum | Utility bean for ensuring that enumeration values do exist in the database. | 
| ExecutionThread | Thread which can be started and will appropriately acquire a session, then
 use the  Executorto complete its work. | 
| Executor.Descriptive | |
| Executor.Impl | |
| Executor.SimpleSqlWork | Simple adapter which takes a String for  Executor.Descriptive.description | 
| Executor.SimpleWork<T> | Simple adapter which takes a String for  Executor.Descriptive.description | 
| IceUtil | Methods for working with Ice. | 
| JvmSettingsCheck | Hook run by the context which prints out JVM-related
 information, primarily Java version, max heap size
 and available processors. | 
| ReadOnlyConfigInit | Propagate the server's read-only status into corresponding keys in the configuration service. | 
| ReadOnlyStatus | Hook run by the context as early as possible to detect if the DB
 connection is read-only. | 
| ServerDirectoryCheck | Hook run by the context at startup to create needed directories for the server. | 
| ServerVersionCheck | Hook run by the context. | 
| ServiceHandler | |
| SleepTimer | Provides a timer for having a thread sleep that prematurely awakens when the server is to shut down,
 so the sleeping does not keep the server running. | 
| TimeoutSetter | Sets timeouts for queries according to event context. | 
| Enum | Description | 
|---|---|
| Executor.Priority | 
Instead of abstract classes, IOC methods and dependency injection is used to provide service interception for the Service (binary) bean classes.