# Library functions available for Java canary
<a name="CloudWatch_Synthetics_Canaries_Java"></a>

The `executeStep` function is used to modularize the canary code and execute it in steps. In CloudWatch Synthetics, a Synthetics step is a way to break down your canary script into a series of clearly defined actions, allowing you to monitor different parts of your application journey separately. For each step, CloudWatch Synthetics does the following:
+ A report, including a summary of step execution details like the duration of a step, *pass* or *fail* status, and so on, is created for each canary run. When you choose a run in the CloudWatch Synthetics console, you can view execution details of each step on the **Step** tab.
+ *SuccessPercent* and *Duration* CloudWatch metrics are emitted for each step, enabling users to monitor availability and latency of each step.

   **Usage** 

  ```
  synthetics.executeStep(stepName,()->{
      try {
          //step code to be executed
          return null;
      } catch (Exception e) {
          throw e;
      }
  }).get();
  ```

   **Parameters** 
  + *stepName*, String (required) – A descriptive name of the Synthetics step
  + *function to execute*, Callable<T> (required) – Represents the tasks to be executed
  + *stepOptions*, `com.amazonaws.synthetics.StepOptions (optional)` – StepOptions object that can be used to configure the step execution. 

    *stepConfiguration*, ` com.amazonaws.synthetics.StepConfiguration`(required as part of the stepOptions)

 **Returns** 

The value returned is *CompletableFuture<T>*.

**Note**  
Synthetics only supports sequential steps. Make sure to call the `.get()` method as shown in the example to ensure that the step completes before proceeding to the subsequent step.