java.lang.Object
- javacard.framework.JCSystem

```
public final class JCSystem
extends Object
```
The JCSystem class includes a collection of methods to control applet execution, resource management, atomic transaction management, object deletion mechanism and inter-applet object sharing in the Java Card environment. All methods in JCSystem class are static methods.
This class also includes methods to control the persistence and transience of objects. The term persistent means that objects and their values persist from one CAD session to the next, indefinitely. Persistent object values are updated atomically using transactions.
The makeTransient...Array() methods can be used to create transient arrays. Transient array data is lost (in an undefined state, but the real data is unavailable) immediately upon power loss, and is reset to the default value at the occurrence of certain events such as card reset or deselect. Updates to the values of transient arrays are not atomic and are not affected by transactions.
The Java Card runtime environment maintains an atomic transaction commit buffer which is initialized on card reset (or power on). When a transaction is in progress, the Java Card runtime environment journals all updates to persistent data space into this buffer so that it can always guarantee, at commit time, that everything in the buffer is written or nothing at all is written. The JCSystem includes methods to control an atomic transaction. See Runtime Environment Specification, Java Card Platform, Classic Edition for details.

See Also:

SystemException, TransactionException, Applet

Field Summary

Fields
Modifier and Type	Field	Description
`static byte`	`ARRAY_TYPE_BOOLEAN`	Constant to indicate boolean array type.
`static byte`	`ARRAY_TYPE_BYTE`	Constant to indicate byte array type.
`static byte`	`ARRAY_TYPE_INT`	Constant to indicate int array type.
`static byte`	`ARRAY_TYPE_OBJECT`	Constant to indicate object array type.
`static byte`	`ARRAY_TYPE_SHORT`	Constant to indicate short array type.
`static short`	`ATTR_READABLE_VIEW`	Constant to configure an array view with the read attribute.
`static short`	`ATTR_WRITABLE_VIEW`	Constant to configure an array view with the write attribute.
`static byte`	`CLEAR_ON_DESELECT`	This event code indicates that the contents of the transient object are cleared to the default value on applet deselection event or in `CLEAR_ON_RESET` cases.
`static byte`	`CLEAR_ON_RESET`	This event code indicates that the contents of the transient object are cleared to the default value on card reset (or power on) event.
`static byte`	`MEMORY_TYPE_PERSISTENT`	Constant to indicate persistent memory type.
`static byte`	`MEMORY_TYPE_TRANSIENT_DESELECT`	Constant to indicate transient memory of CLEAR_ON_DESELECT type.
`static byte`	`MEMORY_TYPE_TRANSIENT_RESET`	Constant to indicate transient memory of CLEAR_ON_RESET type.
`static byte`	`NOT_A_TRANSIENT_OBJECT`	This event code indicates that the object is not transient.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static void`	`abortTransaction()`	Aborts the atomic transaction.
`static void`	`beginTransaction()`	Begins an atomic transaction.
`static void`	`commitTransaction()`	Commits an atomic transaction.
`static AID`	`getAID()`	Returns the Java Card runtime environment-owned instance of the `AID` object associated with the current applet context, or `null` if the `Applet.register()` method has not yet been invoked.
`static Shareable`	`getAppletShareableInterfaceObject(AID serverAID, byte parameter)`	Called by a client applet to get a server applet's shareable interface object.
`static byte`	`getAssignedChannel()`	This method is called to obtain the logical channel number assigned to the currently selected applet instance.
`static short`	`getAttributes(Object view)`	Get the attributes of the specified array view.
`static short`	`getAvailableMemory(byte memoryType)`	Obtains the amount of memory of the specified type that is available to the applet.
`static void`	`getAvailableMemory(byte[] buffer, short offset, byte memoryType)`	Obtains the amount of memory of the specified type that is available to the applet.
`static void`	`getAvailableMemory(short[] buffer, short offset, byte memoryType)`	Obtains the amount of memory of the specified type that is available to the applet.
`static short`	`getMaxCommitCapacity()`	Returns the total number of bytes in the commit buffer.
`static AID`	`getPreviousContextAID()`	Obtains the Java Card runtime environment-owned instance of the `AID` object associated with the previously active applet context.
`static byte`	`getTransactionDepth()`	Returns the current transaction nesting depth level.
`static short`	`getUnusedCommitCapacity()`	Returns the number of bytes left in the commit buffer.
`static short`	`getVersion()`	Returns the current major and minor version of the Java Card API.
`static boolean`	`isAppletActive(AID theApplet)`	This method is used to determine if the specified applet is active on the card.
`static boolean`	`isArrayView(Object object)`	Check whether the specified object is an array view
`static boolean`	`isObjectDeletionSupported()`	This method is used to determine if the implementation for the Java Card platform supports the object deletion mechanism.
`static byte`	`isTransient(Object theObj)`	Checks if the specified object is transient.
`static AID`	`lookupAID(byte[] buffer, short offset, byte length)`	Returns the Java Card runtime environment-owned instance of the `AID` object, if any, encapsulating the specified AID bytes in the `buffer` parameter if there exists a successfully installed applet on the card whose instance AID exactly matches that of the specified AID bytes.
`static Object`	`makeArrayView(Object array, short offset, short length, short attributes, Shareable service)`	Creates an array which is a view on the specified `array` parameter.
`static boolean[]`	`makeBooleanArrayView(boolean[] array, short offset, short length, short attributes, Shareable service)`	Creates a boolean array which is a view on the specified `array` parameter.
`static byte[]`	`makeByteArrayView(byte[] array, short offset, short length, short attributes, Shareable service)`	Creates a byte array which is a view on the specified `array` parameter.
`static Object`	`makeGlobalArray(byte type, short length)`	Creates a global `CLEAR_ON_RESET` transient array of the type specified, with the specified array length.
`static short[]`	`makeShortArrayView(short[] array, short offset, short length, short attributes, Shareable service)`	Creates a short array which is a view on the specified `array` parameter.
`static boolean[]`	`makeTransientBooleanArray(short length, byte event)`	Creates a transient boolean array with the specified array length.
`static byte[]`	`makeTransientByteArray(short length, byte event)`	Creates a transient byte array with the specified array length.
`static Object[]`	`makeTransientObjectArray(short length, byte event)`	Creates a transient array of `Object` with the specified array length.
`static short[]`	`makeTransientShortArray(short length, byte event)`	Creates a transient short array with the specified array length.
`static void`	`requestObjectDeletion()`	This method is invoked by the applet to trigger the object deletion service of the Java Card runtime environment.

Methods inherited from class java.lang.Object
equals

- Field Detail
  - MEMORY_TYPE_PERSISTENT
```
public static final byte MEMORY_TYPE_PERSISTENT
```
    Constant to indicate persistent memory type.
    
    See Also:
    
    Constant Field Values
  - MEMORY_TYPE_TRANSIENT_RESET
```
public static final byte MEMORY_TYPE_TRANSIENT_RESET
```
    Constant to indicate transient memory of CLEAR_ON_RESET type.
    
    See Also:
    
    Constant Field Values
  - MEMORY_TYPE_TRANSIENT_DESELECT
```
public static final byte MEMORY_TYPE_TRANSIENT_DESELECT
```
    Constant to indicate transient memory of CLEAR_ON_DESELECT type.
    
    See Also:
    
    Constant Field Values
  - ARRAY_TYPE_BOOLEAN
```
public static final byte ARRAY_TYPE_BOOLEAN
```
    Constant to indicate boolean array type.
    
    See Also:
    
    Constant Field Values
  - ARRAY_TYPE_BYTE
```
public static final byte ARRAY_TYPE_BYTE
```
    Constant to indicate byte array type.
    
    See Also:
    
    Constant Field Values
  - ARRAY_TYPE_SHORT
```
public static final byte ARRAY_TYPE_SHORT
```
    Constant to indicate short array type.
    
    See Also:
    
    Constant Field Values
  - ARRAY_TYPE_INT
```
public static final byte ARRAY_TYPE_INT
```
    Constant to indicate int array type.
    
    See Also:
    
    Constant Field Values
  - ARRAY_TYPE_OBJECT
```
public static final byte ARRAY_TYPE_OBJECT
```
    Constant to indicate object array type.
    
    See Also:
    
    Constant Field Values
  - ATTR_READABLE_VIEW
```
public static final short ATTR_READABLE_VIEW
```
    Constant to configure an array view with the read attribute.
    
    Since:
    
    3.1
    
    See Also:
    
    Constant Field Values
  - ATTR_WRITABLE_VIEW
```
public static final short ATTR_WRITABLE_VIEW
```
    Constant to configure an array view with the write attribute.
    
    Since:
    
    3.1
    
    See Also:
    
    Constant Field Values
  - NOT_A_TRANSIENT_OBJECT
```
public static final byte NOT_A_TRANSIENT_OBJECT
```
    This event code indicates that the object is not transient.
    
    See Also:
    
    Constant Field Values
  - CLEAR_ON_RESET
```
public static final byte CLEAR_ON_RESET
```
    This event code indicates that the contents of the transient object are cleared to the default value on card reset (or power on) event.
    
    See Also:
    
    Constant Field Values
  - CLEAR_ON_DESELECT
```
public static final byte CLEAR_ON_DESELECT
```
    This event code indicates that the contents of the transient object are cleared to the default value on applet deselection event or in CLEAR_ON_RESET cases.
    Notes:
    
    CLEAR_ON_DESELECT transient objects can be accessed only when the applet which created the object is in the same context as the currently selected applet.
    The Java Card runtime environment will throw a SecurityException if a CLEAR_ON_DESELECT transient object is accessed when the currently selected applet is not in the same context as the applet which created the object.
    See Also:
    
    Constant Field Values
- Method Detail
  - isTransient
```
public static byte isTransient(Object theObj)
```
    Checks if the specified object is transient.
    This method returns a constant indicator as follows :
    
    MEMORY_TYPE_TRANSIENT_RESET if the specified object is a CLEAR_ON_RESET transient array created by one of the makeTransient...Array methods using a CLEAR_ON_RESET event code or a view on such array.
    MEMORY_TYPE_TRANSIENT_DESELECT if the specified object is a CLEAR_ON_DESELECT transient array created by one of the makeTransient...Array methods using a CLEAR_ON_DESELECT event code or a view on such array.
    NOT_A_TRANSIENT_OBJECT for all other objects.
    Parameters:
    
    theObj - the object being queried
    
    Returns:
    
    NOT_A_TRANSIENT_OBJECT, CLEAR_ON_RESET, or CLEAR_ON_DESELECT
    
    See Also:
    
    makeTransientBooleanArray(short, byte), makeTransientByteArray(short, byte), makeTransientShortArray(short, byte), makeTransientObjectArray(short, byte), javacardx.framework.util.intx.JCint.makeTransientIntArray(short, byte)
  - makeTransientBooleanArray
```
public static boolean[] makeTransientBooleanArray(short length,
                                                  byte event)
                                           throws NegativeArraySizeException,
                                                  SystemException
```
    Creates a transient boolean array with the specified array length.
    Parameters:
    
    length - the length of the boolean array
    
    event - the CLEAR_ON... event which causes the array elements to be cleared
    
    Returns:
    
    the new transient boolean array
    
    Throws:
    
    NegativeArraySizeException - if the length parameter is negative
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if event is not a valid event code.
    SystemException.NO_TRANSIENT_SPACE if sufficient transient space is not available.
    SystemException.ILLEGAL_TRANSIENT if the current applet context is not the currently selected applet context and CLEAR_ON_DESELECT is specified.
  - makeTransientByteArray
```
public static byte[] makeTransientByteArray(short length,
                                            byte event)
                                     throws NegativeArraySizeException,
                                            SystemException
```
    Creates a transient byte array with the specified array length.
    Parameters:
    
    length - the length of the byte array
    
    event - the CLEAR_ON... event which causes the array elements to be cleared
    
    Returns:
    
    the new transient byte array
    
    Throws:
    
    NegativeArraySizeException - if the length parameter is negative
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if event is not a valid event code.
    SystemException.NO_TRANSIENT_SPACE if sufficient transient space is not available.
    SystemException.ILLEGAL_TRANSIENT if the current applet context is not the currently selected applet context and CLEAR_ON_DESELECT is specified.
  - makeTransientShortArray
```
public static short[] makeTransientShortArray(short length,
                                              byte event)
                                       throws NegativeArraySizeException,
                                              SystemException
```
    Creates a transient short array with the specified array length.
    Parameters:
    
    length - the length of the short array
    
    event - the CLEAR_ON... event which causes the array elements to be cleared
    
    Returns:
    
    the new transient short array
    
    Throws:
    
    NegativeArraySizeException - if the length parameter is negative
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if event is not a valid event code.
    SystemException.NO_TRANSIENT_SPACE if sufficient transient space is not available.
    SystemException.ILLEGAL_TRANSIENT if the current applet context is not the currently selected applet context and CLEAR_ON_DESELECT is specified.
  - makeTransientObjectArray
```
public static Object[] makeTransientObjectArray(short length,
                                                byte event)
                                         throws NegativeArraySizeException,
                                                SystemException
```
    Creates a transient array of Object with the specified array length.
    Parameters:
    
    length - the length of the Object array
    
    event - the CLEAR_ON... event which causes the array elements to be cleared
    
    Returns:
    
    the new transient Object array
    
    Throws:
    
    NegativeArraySizeException - if the length parameter is negative
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if event is not a valid event code.
    SystemException.NO_TRANSIENT_SPACE if sufficient transient space is not available.
    SystemException.ILLEGAL_TRANSIENT if the current applet context is not the currently selected applet context and CLEAR_ON_DESELECT is specified.
  - makeGlobalArray
```
public static Object makeGlobalArray(byte type,
                                     short length)
```
    Creates a global CLEAR_ON_RESET transient array of the type specified, with the specified array length.
    A global array can be accessed from any applet context. References to global arrays cannot be stored in class variables or instance variables or array components. (See Runtime Environment Specification, Java Card Platform, Classic Edition, section 6.2.2 for details)
    Parameters:
    
    type - the array type - must be one of : ARRAY_TYPE_BOOLEAN, ARRAY_TYPE_BYTE, ARRAY_TYPE_SHORT, ARRAY_TYPE_INT, or ARRAY_TYPE_OBJECT
    
    length - the length of the global transient array
    
    Returns:
    
    the new transient Object array
    
    Throws:
    
    NegativeArraySizeException - if the length parameter is negative
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if type is not a valid type code. An implementation which does not support the "int" type may throw this exception if type is ARRAY_TYPE_INT
    SystemException.NO_TRANSIENT_SPACE if sufficient transient space is not available.
    
    Since:
    
    3.0.4
    
    See Also:
    
    ARRAY_TYPE_BOOLEAN, ARRAY_TYPE_BYTE, ARRAY_TYPE_SHORT, ARRAY_TYPE_INT, ARRAY_TYPE_OBJECT
  - makeArrayView
```
public static Object makeArrayView(Object array,
                                   short offset,
                                   short length,
                                   short attributes,
                                   Shareable service)
```
    Creates an array which is a view on the specified array parameter. The elements of the created array have the same type and are mapped to the corresponding elements in the parent array. Any change in the parent array will be visible in the view and vice versa.
    The layout attributes (transient, persistent, sensitive) of the created array are identical to the array parameter ones.
    In addition, it is possible to create read-only, write-only or R/W views using combinations (bitwise inclusive OR) of the following access attributes:
    
    ATTR_READABLE_VIEW: the elements of the view can be read. If this attribute is not set, any attempt to read elements from the created view will throw a SecurityException
    
    ATTR_WRITABLE_VIEW: the elements of the view can be modified and changes are visible in the actual array and any other view on it. If this attribute is not set, any attempt to write elements in the created view will throw a SecurityException
    
    The attributes requested for the view shall remain consistent with the attributes of the array parameter:
    
    Any attempt to create a view with the ATTR_READABLE_VIEW attribute will throw a SecurityException if the array parameter is not readable.
    Any attempt to create a view with the ATTR_WRITABLE_VIEW attribute will throw a SecurityException if the array parameter is not writable.
    
    The created view is temporary and any attempt to store the reference into a class or instance field or in array elements will throw a SecurityException
    Example:
    
    // creates a R/W view of 5 bytes on array, starting at offset 4 byte[] view = (byte[]) JCSystem.makeArrayView(array, (short) 4, (short) 5, (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), null);
    
    Note:
    If the service parameter is non-null, the method returns an object created in the context of the specified service and should be used as parameter when calling methods of this service. Other operations executed in current context, including casting, will throw a SecurityException.
    Parameters:
    
    array - the array on which to create the view (either an actual array or a view)
    
    offset - the offset in the array where the view starts
    
    length - the number of elements in the view
    
    attributes - the view access attributes (combinations of ATTR_READABLE_VIEW and ATTR_WRITABLE_VIEW attributes)
    
    service - the shareable object identifying the recipient context of the new view. If null, the view will remain in the current context. If non-null, the method returns an object created in the context of the specified service and should be used as parameter when calling methods of this service. Other operations executed in current context, including casting, will throw a SecurityException.
    
    Returns:
    
    a view on the specified array parameter
    
    Throws:
    
    NullPointerException - if the array parameter is null
    
    NegativeArraySizeException - if the length parameter is negative
    
    SecurityException -
    
    if the array cannot be accessed from current context
    
    if requesting access attributes that were not available for the array parameter
    
    SystemException - with the following reason code:
    
    SystemException.ILLEGAL_VALUE if the array parameter is not an array
    
    SystemException.NO_RESOURCE if not enough resources to allocate the view
    
    ArrayIndexOutOfBoundsException - if the view would cause access of data outside array bounds
    
    Since:
    
    3.1
    
    See Also:
    
    makeBooleanArrayView(boolean[], short, short, short, Shareable), makeByteArrayView(byte[], short, short, short, Shareable), makeShortArrayView(short[], short, short, short, Shareable)
  - makeBooleanArrayView
```
public static boolean[] makeBooleanArrayView(boolean[] array,
                                             short offset,
                                             short length,
                                             short attributes,
                                             Shareable service)
```
    Creates a boolean array which is a view on the specified array parameter. The elements of the created array are mapped to the corresponding elements in the parent array. Any change in the parent array will be visible in the view and vice versa.
    The layout attributes (transient, persistent, sensitive) of the created array are identical to the array parameter ones.
    In addition, it is possible to create read-only, write-only or R/W views using combinations (bitwise inclusive OR) of the following access attributes:
    
    ATTR_READABLE_VIEW: the elements of the view can be read. If this attribute is not set, any attempt to read elements from the created view will throw a SecurityException
    
    ATTR_WRITABLE_VIEW: the elements of the view can be modified and changes are visible in the actual array and any other view on it. If this attribute is not set, any attempt to write elements in the created view will throw a SecurityException
    
    The attributes requested for the view shall remain consistent with the attributes of the array parameter:
    
    Any attempt to create a view with the ATTR_READABLE_VIEW attribute will throw a SecurityException if the array parameter is not readable.
    Any attempt to create a view with the ATTR_WRITABLE_VIEW attribute will throw a SecurityException if the array parameter is not writable.
    
    The created view is temporary and any attempt to store the reference into a class or instance field or in array elements will throw a SecurityException
    Example:
    
    // creates a R/W view of 5 boolean on array, starting at offset 4 boolean[] view = JCSystem.makeBooleanArrayView(array, (short) 4, (short) 5, (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), null); // creates a view in the service context and share it with the service boolean[] view = JCSystem.makeBooleanArrayView(array, (short) 4, (short) 5, (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), service); service.execute(view);
    Parameters:
    
    array - the array on which to create the view (either an actual array or a view)
    
    offset - the offset in the array where the view starts
    
    length - the number of elements in the view
    
    attributes - the view access attributes (combinations of ATTR_READABLE_VIEW and ATTR_WRITABLE_VIEW attributes)
    
    service - the shareable object identifying the recipient context of the new view. If null, the view will remain in the current context. If non-null, the method returns an object created in the context of the specified service and should be used as parameter when calling methods of this service. Other operations executed in current context, including casting, will throw a SecurityException.
    
    Returns:
    
    a view on the specified array parameter
    
    Throws:
    
    NullPointerException - if the array parameter is null
    
    NegativeArraySizeException - if the length parameter is negative
    
    SecurityException -
    
    if the array cannot be accessed from current context
    
    if requesting access attributes that were not available for the array parameter
    
    SystemException - with the following reason code:
    
    SystemException.ILLEGAL_VALUE if the array parameter is not an array
    
    SystemException.NO_RESOURCE if not enough resources to allocate the view
    
    ArrayIndexOutOfBoundsException - if the view would cause access of data outside array bounds
    
    Since:
    
    3.1
  - makeByteArrayView
```
public static byte[] makeByteArrayView(byte[] array,
                                       short offset,
                                       short length,
                                       short attributes,
                                       Shareable service)
```
    Creates a byte array which is a view on the specified array parameter. The elements of the created array have the same type and are mapped to the corresponding elements in the parent array. Any change in the parent array will be visible in the view and vice versa.
    The layout attributes (transient, persistent, sensitive) of the created array are identical to the array parameter ones.
    In addition, it is possible to create read-only, write-only or R/W views using combinations (bitwise inclusive OR) of the following access attributes:
    
    ATTR_READABLE_VIEW: the elements of the view can be read. If this attribute is not set, any attempt to read elements from the created view will throw a SecurityException
    
    ATTR_WRITABLE_VIEW: the elements of the view can be modified and changes are visible in the actual array and any other view on it. If this attribute is not set, any attempt to write elements in the created view will throw a SecurityException
    
    The attributes requested for the view shall remain consistent with the attributes of the array parameter:
    
    Any attempt to create a view with the ATTR_READABLE_VIEW attribute will throw a SecurityException if the array parameter is not readable.
    Any attempt to create a view with the ATTR_WRITABLE_VIEW attribute will throw a SecurityException if the array parameter is not writable.
    
    The created view is temporary and any attempt to store the reference into a class or instance field or in array elements will throw a SecurityException
    Example:
    
    // creates a R/W view of 5 bytes on array, starting at offset 4 byte[] view = JCSystem.makeByteArrayView(array, (short) 4, (short) 5, (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), null); // creates a view in the service context and share it with the service byte[] view = JCSystem.makeByteArrayView(array, (short) 4, (short) 5, (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), service); service.execute(view);
    Parameters:
    
    array - the array on which to create the view (either an actual array or a view)
    
    offset - the offset in the array where the view starts
    
    length - the number of elements in the view
    
    attributes - the view access attributes (combinations of ATTR_READABLE_VIEW and ATTR_WRITABLE_VIEW attributes)
    
    service - the shareable object identifying the recipient context of the new view. If null, the view will remain in the current context. If non-null, the method returns an object created in the context of the specified service and should be used as parameter when calling methods of this service. Other operations executed in current context, including casting, will throw a SecurityException.
    
    Returns:
    
    a view on the specified array parameter
    
    Throws:
    
    NullPointerException - if the array parameter is null
    
    NegativeArraySizeException - if the length parameter is negative
    
    SecurityException -
    
    if the array cannot be accessed from current context
    
    if requesting access attributes that were not available for the array parameter
    
    SystemException - with the following reason code:
    
    SystemException.ILLEGAL_VALUE if the array parameter is not an array
    
    SystemException.NO_RESOURCE if not enough resources to allocate the view
    
    ArrayIndexOutOfBoundsException - if the view would cause access of data outside array bounds
    
    Since:
    
    3.1
  - makeShortArrayView
```
public static short[] makeShortArrayView(short[] array,
                                         short offset,
                                         short length,
                                         short attributes,
                                         Shareable service)
```
    Creates a short array which is a view on the specified array parameter. The elements of the created array are mapped to the corresponding elements in the parent array. Any change in the parent array will be visible in the view and vice versa.
    The layout attributes (transient, persistent, sensitive) of the created array are identical to the array parameter ones.
    In addition, it is possible to create read-only, write-only or R/W views using combinations (bitwise inclusive OR) of the following access attributes:
    
    ATTR_READABLE_VIEW: the elements of the view can be read. If this attribute is not set, any attempt to read elements from the created view will throw a SecurityException
    
    ATTR_WRITABLE_VIEW: the elements of the view can be modified and changes are visible in the actual array and any other view on it. If this attribute is not set, any attempt to write elements in the created view will throw a SecurityException
    
    The attributes requested for the view shall remain consistent with the attributes of the array parameter:
    
    Any attempt to create a view with the ATTR_READABLE_VIEW attribute will throw a SecurityException if the array parameter is not readable.
    Any attempt to create a view with the ATTR_WRITABLE_VIEW attribute will throw a SecurityException if the array parameter is not writable.
    
    The created view is temporary and any attempt to store the reference into a class or instance field or in array elements will throw a SecurityException
    Example:
    
    // creates a R/W view of 5 short on array, starting at offset 4 short[] view = JCSystem.makeShortArrayView(array, (short) 4, (short) 5, (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), null); // creates a view in the service context and share it with the service short[] view = JCSystem.makeShortArrayView(array, (short) 4, (short) 5, (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), service); service.execute(view);
    Parameters:
    
    array - the array on which to create the view (either an actual array or a view)
    
    offset - the offset in the array where the view starts
    
    length - the number of elements in the view
    
    attributes - the view access attributes (combinations of ATTR_READABLE_VIEW and ATTR_WRITABLE_VIEW attributes)
    
    service - the shareable object identifying the recipient context of the new view. If null, the view will remain in the current context. If non-null, the method returns an object created in the context of the specified service and should be used as parameter when calling methods of this service. Other operations executed in current context, including casting, will throw a SecurityException.
    
    Returns:
    
    a view on the specified array parameter
    
    Throws:
    
    NullPointerException - if the array parameter is null
    
    NegativeArraySizeException - if the length parameter is negative
    
    SecurityException -
    
    if the array cannot be accessed from current context
    
    if requesting access attributes that were not available for the array parameter
    
    SystemException - with the following reason code:
    
    SystemException.ILLEGAL_VALUE if the array parameter is not an array
    
    SystemException.NO_RESOURCE if not enough resources to allocate the view
    
    ArrayIndexOutOfBoundsException - if the view would cause access of data outside array bounds
    
    Since:
    
    3.1
  - isArrayView
```
public static boolean isArrayView(Object object)
```
    Check whether the specified object is an array view
    
    Parameters:
    
    object - the object to query
    
    Returns:
    
    true if the object parameter is an array view, false otherwise
    
    Since:
    
    3.1
    
    See Also:
    
    makeArrayView(Object, short, short, short, Shareable)
  - getAttributes
```
public static short getAttributes(Object view)
                           throws SystemException
```
    Get the attributes of the specified array view.
    The attributes returned are combinations (bitwise inclusive OR) of the following access attributes:
    
    ATTR_READABLE_VIEW: the elements of the view can be read. If this attribute is not set, any attempt to read elements from the view will throw a SecurityException
    
    ATTR_WRITABLE_VIEW: the elements of the view can be modified and changes are visible in the actual array and any other view on it. If this attribute is not set, any attempt to write elements in the view will throw a SecurityException
    Parameters:
    
    view - the object to query
    
    Returns:
    
    the attributes (ATTR_READABLE_VIEW, ATTR_WRITABLE_VIEW) of the view
    
    Throws:
    
    SystemException - with the following reason code
    
    SystemException.ILLEGAL_VALUE if the object is not a view
    
    Since:
    
    3.1
    
    See Also:
    
    makeArrayView(Object, short, short, short, Shareable)
  - getVersion
```
public static short getVersion()
```
    Returns the current major and minor version of the Java Card API.
    
    Returns:
    
    version number as byte.byte (major.minor)
  - getAID
```
public static AID getAID()
```
    Returns the Java Card runtime environment-owned instance of the AID object associated with the current applet context, or null if the Applet.register() method has not yet been invoked.
    Java Card runtime environment-owned instances of AID are permanent Java Card runtime environment Entry Point Objects and can be accessed from any applet context. References to these permanent objects can be stored and re-used.
    See Runtime Environment Specification, Java Card Platform, Classic Edition, section 6.2.1 for details.
    In addition to returning an Object reference result, this method sets the result in an internal state which can be rechecked using assertion methods of the SensitiveResult class, if supported by the platform.
    
    Returns:
    
    the AID object
  - lookupAID
```
public static AID lookupAID(byte[] buffer,
                            short offset,
                            byte length)
```
    Returns the Java Card runtime environment-owned instance of the AID object, if any, encapsulating the specified AID bytes in the buffer parameter if there exists a successfully installed applet on the card whose instance AID exactly matches that of the specified AID bytes.
    Java Card runtime environment-owned instances of AID are permanent Java Card runtime environment Entry Point Objects and can be accessed from any applet context. References to these permanent objects can be stored and re-used.
    See Runtime Environment Specification, Java Card Platform, Classic Edition, section 6.2.1 for details.
    In addition to returning an Object reference result, this method sets the result in an internal state which can be rechecked using assertion methods of the SensitiveResult class, if supported by the platform.
    
    Parameters:
    
    buffer - byte array containing the AID bytes
    
    offset - offset within buffer where AID bytes begin
    
    length - length of AID bytes in buffer
    
    Returns:
    
    the AID object, if any; null otherwise. A VM exception is thrown if buffer is null, or if offset or length are out of range.
  - beginTransaction
```
public static void beginTransaction()
                             throws TransactionException
```
    Begins an atomic transaction. If a transaction is already in progress (transaction nesting depth level != 0), a TransactionException is thrown.
    Note:
    
    This method may do nothing if the Applet.register() method has not yet been invoked. In case of tear or failure prior to successful registration, the Java Card runtime environment will roll back all atomically updated persistent state.
    Throws:
    
    TransactionException - with the following reason codes:
    
    TransactionException.IN_PROGRESS if a transaction is already in progress.
    
    See Also:
    
    commitTransaction(), abortTransaction()
  - abortTransaction
```
public static void abortTransaction()
                             throws TransactionException
```
    Aborts the atomic transaction. The contents of the commit buffer is discarded.
    Note:
    
    This method may do nothing if the Applet.register() method has not yet been invoked. In case of tear or failure prior to successful registration, the Java Card runtime environment will roll back all atomically updated persistent state.
    Do not call this method from within a transaction which creates new objects because the Java Card runtime environment may not recover the heap space used by the new object instances.
    Do not call this method from within a transaction which creates new objects because the Java Card runtime environment may, to ensure the security of the card and to avoid heap space loss, lock up the card session to force tear/reset processing.
    The Java Card runtime environment ensures that any variable of reference type which references an object instantiated from within this aborted transaction is equivalent to a null reference.
    Throws:
    
    TransactionException - with the following reason codes:
    
    TransactionException.NOT_IN_PROGRESS if a transaction is not in progress.
    
    See Also:
    
    beginTransaction(), commitTransaction()
  - commitTransaction
```
public static void commitTransaction()
                              throws TransactionException
```
    Commits an atomic transaction. The contents of commit buffer is atomically committed. If a transaction is not in progress (transaction nesting depth level == 0) then a TransactionException is thrown.
    Note:
    
    This method may do nothing if the Applet.register() method has not yet been invoked. In case of tear or failure prior to successful registration, the Java Card runtime environment will roll back all atomically updated persistent state.
    Throws:
    
    TransactionException - with the following reason codes:
    
    TransactionException.NOT_IN_PROGRESS if a transaction is not in progress.
    
    See Also:
    
    beginTransaction(), abortTransaction()
  - getTransactionDepth
```
public static byte getTransactionDepth()
```
    Returns the current transaction nesting depth level. At present, only 1 transaction can be in progress at a time.
    
    Returns:
    
    1 if transaction in progress, 0 if not
  - getUnusedCommitCapacity
```
public static short getUnusedCommitCapacity()
```
    Returns the number of bytes left in the commit buffer.
    Note:
    
    If the number of bytes left in the commit buffer is greater than 32767, then this method returns 32767.
    Returns:
    
    the number of bytes left in the commit buffer
    
    See Also:
    
    getMaxCommitCapacity()
  - getMaxCommitCapacity
```
public static short getMaxCommitCapacity()
```
    Returns the total number of bytes in the commit buffer. This is approximately the maximum number of bytes of persistent data which can be modified during a transaction. However, the transaction subsystem requires additional bytes of overhead data to be included in the commit buffer, and this depends on the number of fields modified and the implementation of the transaction subsystem. The application cannot determine the actual maximum amount of data which can be modified during a transaction without taking these overhead bytes into consideration.
    Note:
    
    If the total number of bytes in the commit buffer is greater than 32767, then this method returns 32767.
    Returns:
    
    the total number of bytes in the commit buffer
    
    See Also:
    
    getUnusedCommitCapacity()
  - getPreviousContextAID
```
public static AID getPreviousContextAID()
```
    Obtains the Java Card runtime environment-owned instance of the AID object associated with the previously active applet context. This method is typically used by a server applet, while executing a shareable interface method to determine the identity of its client and thereby control access privileges.
    Java Card runtime environment-owned instances of AID are permanent Java Card runtime environment Entry Point Objects and can be accessed from any applet context. References to these permanent objects can be stored and re-used.
    See Runtime Environment Specification, Java Card Platform, Classic Edition, section 6.2.1 for details.
    In addition to returning an Object reference result, this method sets the result in an internal state which can be rechecked using assertion methods of the SensitiveResult class, if supported by the platform.
    
    Returns:
    
    the AID object of the previous context, or null if Java Card runtime environment
  - getAvailableMemory
```
public static short getAvailableMemory(byte memoryType)
                                throws SystemException
```
    Obtains the amount of memory of the specified type that is available to the applet. Note that implementation-dependent memory overhead structures may also use the same memory pool.
    Notes:
    
    The number of bytes returned is only an upper bound on the amount of memory available due to overhead requirements.
    Allocation of CLEAR_ON_RESET transient objects may affect the amount of CLEAR_ON_DESELECT transient memory available.
    Allocation of CLEAR_ON_DESELECT transient objects may affect the amount of CLEAR_ON_RESET transient memory available.
    If the number of available bytes is greater than 32767, then this method returns 32767. Please use getAvailableMemory(short[],short) method for accurate information.
    The returned count is not an indicator of the size of object which may be created since memory fragmentation is possible.
    Parameters:
    
    memoryType - the type of memory being queried. One of the MEMORY_TYPE_* constants defined above, for example MEMORY_TYPE_PERSISTENT.
    
    Returns:
    
    the upper bound on available bytes of memory for the specified type
    
    Throws:
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if memoryType is not a valid memory type.
    
    See Also:
    
    getAvailableMemory(short[], short, byte)
  - getAvailableMemory
```
public static void getAvailableMemory(short[] buffer,
                                      short offset,
                                      byte memoryType)
                               throws SystemException
```
    Obtains the amount of memory of the specified type that is available to the applet. Note that implementation-dependent memory overhead structures may also use the same memory pool. The requested memory information is returned as a 32 bit number stored in the specified short array - buffer. The 32 bit number is the concatenation of buffer[offset] and buffer[offset+1].
    Notes:
    
    The number of bytes returned is only an upper bound on the amount of memory available due to overhead requirements.
    Allocation of CLEAR_ON_RESET transient objects may affect the amount of CLEAR_ON_DESELECT transient memory available.
    Allocation of CLEAR_ON_DESELECT transient objects may affect the amount of CLEAR_ON_RESET transient memory available.
    The 32 bit number is not an indicator of the size of object which may be created since memory fragmentation is possible.
    Parameters:
    
    memoryType - the type of memory being queried. One of the MEMORY_TYPE_* constants defined above, for example MEMORY_TYPE_PERSISTENT.
    
    buffer - the output buffer for storing memory size information
    
    offset - the offset within the buffer where memory size information begins
    
    Throws:
    
    ArrayIndexOutOfBoundsException - if buffer[offset] or buffer[offset+1] outside array bounds
    
    NullPointerException - if buffer is null
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if memoryType is not a valid memory type.
    
    Since:
    
    3.0.4
  - getAvailableMemory
```
public static void getAvailableMemory(byte[] buffer,
                                      short offset,
                                      byte memoryType)
                               throws SystemException
```
    Obtains the amount of memory of the specified type that is available to the applet. Note that implementation-dependent memory overhead structures may also use the same memory pool. The requested memory information is returned as a 32 bit number stored in the specified short array - buffer. The 32 bit number is the concatenation of buffer[offset], buffer[offset+1], buffer[offset+2] and buffer[offset+3].
    Notes:
    
    The number of bytes returned is only an upper bound on the amount of memory available due to overhead requirements.
    Allocation of CLEAR_ON_RESET transient objects may affect the amount of CLEAR_ON_DESELECT transient memory available.
    Allocation of CLEAR_ON_DESELECT transient objects may affect the amount of CLEAR_ON_RESET transient memory available.
    The 32 bit number is not an indicator of the size of object which may be created since memory fragmentation is possible.
    Parameters:
    
    memoryType - the type of memory being queried. One of the MEMORY_TYPE_* constants defined above, for example MEMORY_TYPE_PERSISTENT.
    
    buffer - the output buffer for storing memory size information
    
    offset - the offset within the buffer where memory size information begins
    
    Throws:
    
    ArrayIndexOutOfBoundsException - if buffer[offset] or buffer[offset+3] outside array bounds
    
    NullPointerException - if buffer is null
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_VALUE if memoryType is not a valid memory type.
    
    Since:
    
    3.2
  - getAppletShareableInterfaceObject
```
public static Shareable getAppletShareableInterfaceObject(AID serverAID,
                                                          byte parameter)
```
    Called by a client applet to get a server applet's shareable interface object.
    This method returns null if:
    
    the Applet.register() has not yet been invoked
    
    the serverAID parameter is null or the server applet does not exist
    
    the server applet returns null
    
    the server applet throws an uncaught exception
    
    In addition to returning an Object reference result, this method sets the result in an internal state which can be rechecked using assertion methods of the SensitiveResult class, if supported by the platform.
    Parameters:
    
    serverAID - the AID of the server applet
    
    parameter - optional parameter data
    
    Returns:
    
    the shareable interface object or null
    
    Throws:
    
    SecurityException - if the server applet is not multiselectable and is currently active either on another logical channel or on any other I/O interface.
    
    See Also:
    
    Applet.getShareableInterfaceObject(AID, byte)
  - isObjectDeletionSupported
```
public static boolean isObjectDeletionSupported()
```
    This method is used to determine if the implementation for the Java Card platform supports the object deletion mechanism.
    
    Returns:
    
    true if the object deletion mechanism is supported, false otherwise
  - requestObjectDeletion
```
public static void requestObjectDeletion()
                                  throws SystemException
```
    This method is invoked by the applet to trigger the object deletion service of the Java Card runtime environment. If the Java Card runtime environment implements the object deletion mechanism, the request is merely logged at this time. The Java Card runtime environment must schedule the object deletion service prior to the next invocation of the Applet.process() method. The object deletion mechanism must ensure that :
    
    Any unreferenced persistent object owned by the current applet context is deleted and the associated space is recovered for reuse prior to the next invocation of the Applet.process() method.
    Any unreferenced CLEAR_ON_DESELECT or CLEAR_ON_RESET transient object owned by the current applet context is deleted and the associated space is recovered for reuse before the next card reset session.
    Throws:
    
    SystemException - with the following reason codes:
    
    SystemException.ILLEGAL_USE if the object deletion mechanism is not implemented.
  - getAssignedChannel
```
public static byte getAssignedChannel()
```
    This method is called to obtain the logical channel number assigned to the currently selected applet instance. The assigned logical channel is the logical channel on which the currently selected applet instance is or will be the active applet instance. This logical channel number is always equal to the origin logical channel number returned by the APDU.getCLAChannel() method except during selection and deselection via the MANAGE CHANNEL APDU command. If this method is called from the Applet.select(), Applet.deselect(), MultiSelectable.select(boolean) and MultiSelectable.deselect(boolean) methods during MANAGE CHANNEL APDU command processing, the logical channel number returned may be different.
    See Runtime Environment Specification, Java Card Platform, Classic Edition, sections 4, 4.4, 4.5 for details.
    
    Returns:
    
    the logical channel number in the range 0-19 assigned to the currently selected applet instance
    
    See Also:
    
    APDU.getCLAChannel()
  - isAppletActive
```
public static boolean isAppletActive(AID theApplet)
```
    This method is used to determine if the specified applet is active on the card.
    Note:
    
    This method returns false if the specified applet is not active, even if its context is active.
    This method returns false if the specified applet has not successfully registered via Applet.register.
    If successfully registered, this method returns true even in the Applet.install, and Applet.select methods.
    Parameters:
    
    theApplet - the AID of the applet object being queried
    
    Returns:
    
    true if and only if the applet specified by the AID parameter is currently active on this or another logical channel parameter is currently active either on this or another logical channel or on any other I/O interface.
    
    See Also:
    
    lookupAID( byte[] buffer, short offset, byte length )

Class JCSystem

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MEMORY_TYPE_PERSISTENT

MEMORY_TYPE_TRANSIENT_RESET

MEMORY_TYPE_TRANSIENT_DESELECT

ARRAY_TYPE_BOOLEAN

ARRAY_TYPE_BYTE

ARRAY_TYPE_SHORT

ARRAY_TYPE_INT

ARRAY_TYPE_OBJECT

ATTR_READABLE_VIEW

ATTR_WRITABLE_VIEW

NOT_A_TRANSIENT_OBJECT

CLEAR_ON_RESET

CLEAR_ON_DESELECT

Method Detail

isTransient

makeTransientBooleanArray

makeTransientByteArray

makeTransientShortArray

makeTransientObjectArray

makeGlobalArray

makeArrayView

makeBooleanArrayView

makeByteArrayView

makeShortArrayView

isArrayView

getAttributes

getVersion

getAID

lookupAID

beginTransaction

abortTransaction

commitTransaction

getTransactionDepth

getUnusedCommitCapacity

getMaxCommitCapacity

getPreviousContextAID

getAvailableMemory

getAvailableMemory

getAvailableMemory

getAppletShareableInterfaceObject

isObjectDeletionSupported

requestObjectDeletion

getAssignedChannel

isAppletActive