This document describes additional changes to the specification of JSR 392 which is defined by the Final Release in September 2021.
When specification text is provided, insertions are shown on a light green background and deletions are shown struck through on a light red background. Links to pages outside of those explicitly changed by this specification may not be functional.
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| Contents | |
|---|---|
| 1 | Version Identification |
| 2 | java.specification.maintenance.version |
| 3 | Modern Desktop Support |
| 4 | Key Encapsulation Mechanism API |
There is no change to the values returned by the system properties
java.specification.version and
java.vm.specification.version. They continue to report
"17". The value returned by the newly defined system
property
java.specification.maintenance.version is
"1".
Add a new system property,
java.specification.maintenance.version, which returns the
maintenance release number of the Java SE specification being implemented
by the JDK.
Add the system property to the table in the specification
of System.getProperties():
java.specification.maintenance.version
Java Runtime Environment specification maintenance version, may be
interpreted as a positive integer (optional, see below)
Add the following details to the specification of
System.getProperties():
The java.specification.maintenance.version property is
defined if the specification implemented by this runtime at the time of
its construction had undergone a
maintenance
release. When defined, its value identifies that maintenance
release. To indicate the first maintenance release this property will have
the value "1", to indicate the second maintenance release,
this property will have the value "2", and so on.
The Change Specification Request (CSR) associated with this change is
8330418.
This specification of java.specification.maintenance.version
aligns with the corresponding specification in the
Final Release of Java SE 19.
Update the java.awt.Robot specification to describe how it
may operate in modern desktop environments which do not automatically
give applications full access to the screen.
Append the following text to the class specification:
Platforms and desktop environments may impose restrictions or limitations on the access required to implement all functionality in the Robot class. For example:
The Robot API specification requires that approvals for these be granted for full operation. If they are not granted, the API will be degraded as discussed here. Relevant specific API methods may document more specific limitations and requirements. Depending on the policies of the desktop environment, the approvals mentioned above may:
When such approvals need to given interactively, it may impede the normal operation of the application until approved, and if approval is denied or not possible, or cannot be made persistent then it will degrade the functionality of this class and in turn any part of the operation of the application which is dependent on it.
Augment the specification of mouseMove(int, int) to describe
acceptable behaviour:
The mouse pointer may not visually move on some platforms, while the subsequent mousePress and mouseRelease can be delivered to the correct location
Update the specification of getPixelColor(int, int) to allow
for degraded behaviour if the required permissions are missing.
Returns the color of a pixel at the given screen coordinates.
If the desktop environment requires that permissions be granted to
capture screen content, and the required permissions are not granted,
then a SecurityException may be thrown, or the content of
the returned Color is undefined.
It is recommended to avoid calling this method on the AWT Event Dispatch Thread since screen capture may be a lengthy operation, particularly if acquiring permissions is needed and involves user interaction.
SecurityException may be
thrown:
SecurityException - if readDisplayPixels
permission is not granted, or access to the screen is denied by the
desktop environment
Similarly, update the specification of
createScreenCapture(Rectangle) to allow for degraded
behaviour if the required permissions are missing:
Creates an image containing pixels read from the screen. This image does not include the mouse cursor.
If the desktop environment requires that permissions be granted to
capture screen content, and the required permissions are not granted,
then a SecurityException may be thrown, or the content of
the returned BufferedImage is undefined.
It is recommended to avoid calling this method on the AWT Event Dispatch Thread since screen capture may be a lengthy operation, particularly if acquiring permissions is needed and involves user interaction.
SecurityException:
SecurityException - if readDisplayPixels
permission is not
granted,
or access to the screen is denied by the desktop environment
Finally, update the specification of
createMultiResolutionScreenCapture(Rectangle) to allow for
degraded behaviour if the required permissions are missing.
Creates an image containing pixels read from the screen.
This image does not include the mouse cursor.
This method can be used in case there is a scaling transform from
user space to screen (device) space. Typically this means that the
display is a high resolution screen, although strictly it means any
case in which there is such a tranform. Returns
a MultiResolutionImage.
SecurityException.
SecurityException - if readDisplayPixels
permission is not
granted,
or access to the screen is denied by the desktop environment
The Change Specification Request (CSR) associated with these changes is 8330603. This specification aligns with the corresponding specification in the Final Release of Java SE 21.
The Key Encapsulation Mechanism (KEM) API was added to Java SE 21 with JEP 452 (Key Encapsulation Mechanism API). This API supports secure encryption techniques to derive symmetric keys using public key cryptography. It provides functionality required by some Post-Quantum Cryptographic (PQC) algorithms and is necessary to support all of the candidate algorithms currently identified by the U.S. National Institute of Standards and Technology (NIST) for PQC standardization.
The following classes were added to module java.base,
package javax.crypto:
The Change Specification Request (CSR) associated with this change is
8330545. This
specification aligns with the corresponding specifications of
KEM,
KEM.Encapsulator,
KEM.Decapsulator,
KEM.Encapsulated,
KEMSpi,
KEMSpi.EncapsulatorSpi,
KEMSpi.DecapsulatorSpi, and
DecapsulateException
in the
Final Release of Java SE 21.