---
title: "unwrap Method (SQLServerCallableStatement) | Microsoft Docs"
ms.custom: ""
ms.date: "01/19/2017"
ms.prod: sql
ms.prod_service: connectivity
ms.reviewer: ""
ms.technology: connectivity
ms.topic: conceptual
ms.assetid: cbbf2728-b8c8-4c35-875a-6e967c8285dc
author: David-Engel
ms.author: v-daenge
---
# unwrap Method (SQLServerCallableStatement)
[!INCLUDE[Driver_JDBC_Download](../../../includes/driver_jdbc_download.md)]

  Returns an object that implements the specified interface to allow access to the [!INCLUDE[jdbcNoVersion](../../../includes/jdbcnoversion_md.md)]-specific methods.  
  
## Syntax  
  
```  
  
public <T> T unwrap(Class<T> iface)  
```  
  
#### Parameters  
 *iface*  
  
 A class of type **T** defining an interface.  
  
## Return Value  
 An object that implements the specified interface.  
  
## Exceptions  
 [SQLServerException](../../../connect/jdbc/reference/sqlserverexception-class.md)  
  
## Remarks  
 The [unwrap](../../../connect/jdbc/reference/unwrap-method-sqlservercallablestatement.md) method is defined by the java.sql.Wrapper interface, which is introduced in the JDBC 4.0 Spec.  
  
 Applications might need to access extensions to the JDBC API that are specific to the [!INCLUDE[jdbcNoVersion](../../../includes/jdbcnoversion_md.md)]. The unwrap method supports unwrapping to public classes that this object extends, if the classes expose vendor extensions.  
  
 [SQLServerCallableStatement](../../../connect/jdbc/reference/sqlservercallablestatement-class.md) implements [ISQLServerPreparedStatement](../../../connect/jdbc/reference/sqlserverpreparedstatement-class.md), which is extended from the [ISQLServerStatement](../../../connect/jdbc/reference/sqlserverstatement-class.md). When this method is called, the object unwraps to the following classes: [SQLServerStatement](../../../connect/jdbc/reference/sqlserverstatement-class.md), [SQLServerPreparedStatement](../../../connect/jdbc/reference/sqlserverpreparedstatement-class.md), and [SQLServerCallableStatement](../../../connect/jdbc/reference/sqlservercallablestatement-class.md).  
  
 For more information, see [Wrappers and Interfaces](../../../connect/jdbc/wrappers-and-interfaces.md).  
  
 The following code example demonstrates how to use the isWrapperFor and unwrap methods to check the driver extensions and invoke the vendor-specific methods, such as [setResponseBuffering](../../../connect/jdbc/reference/setresponsebuffering-method-sqlserverstatement.md) and [getResponseBuffering](../../../connect/jdbc/reference/getresponsebuffering-method-sqlserverstatement.md).  
  
```  
public static void executeStoredProcedure(Connection con) {  
   try {  
    CallableStatement cstmt =   
       con.prepareCall("{call dbo.stored_proc_name(?, ?)}");  
  
    // The recommended way to access the JDBC   
    // Driver-specific methods is to use the JDBC 4.0 Wrapper   
    // functionality.   
    // The following code statements demonstrates how to use the   
    // isWrapperFor and unwrap methods  
    // to access the driver-specific response buffering methods.  
  
    if (cstmt.isWrapperFor(  
      com.microsoft.sqlserver.jdbc.SQLServerCallableStatement.class)) {  
     // The CallableStatement object can unwrap to   
     // SQLServerCallableStatement.  
     SQLServerCallableStatement SQLcstmt =   
     cstmt.unwrap(  
        com.microsoft.sqlserver.jdbc.SQLServerCallableStatement.class);  
     SQLcstmt.setResponseBuffering("adaptive");  
     System.out.println("Response buffering mode has been set to " +  
         SQLcstmt.getResponseBuffering());  
     }  
  
    if (cstmt.isWrapperFor(  
      com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.class)) {  
      // The CallableStatement object can unwrap to   
      // SQLServerPreparedStatement.                    
      SQLServerPreparedStatement SQLpstmt =   
       cstmt.unwrap(  
       com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.class);  
      SQLpstmt.setResponseBuffering("adaptive");  
      System.out.println("Response buffering mode has been set to " +  
          SQLpstmt.getResponseBuffering());  
    }  
    if (cstmt.isWrapperFor(  
      com.microsoft.sqlserver.jdbc.SQLServerStatement.class)) {  
  
      // The CallableStatement object can unwrap to SQLServerStatement.   
      SQLServerStatement SQLstmt =   
        cstmt.unwrap(  
        com.microsoft.sqlserver.jdbc.SQLServerStatement.class);  
      SQLstmt.setResponseBuffering("adaptive");  
      System.out.println("Response buffering mode has been set to " +  
      SQLstmt.getResponseBuffering());  
    }  
  }  
  catch (Exception e) {  
     e.printStackTrace();  
  }  
}   
```  
  
## See Also  
 [isWrapperFor Method &#40;SQLServerCallableStatement&#41;](../../../connect/jdbc/reference/iswrapperfor-method-sqlservercallablestatement.md)   
 [SQLServerCallableStatement Members](../../../connect/jdbc/reference/sqlservercallablestatement-members.md)   
 [SQLServerCallableStatement Class](../../../connect/jdbc/reference/sqlservercallablestatement-class.md)