This Specification defines version 11 of the Java Platform, Standard Edition.
|4||Component JSR Specifications|
|9||APIs proposed for removal|
|10||Non-API features removed|
|A1||Complete API Specification|
|A2||API Specification differences|
|A3||Java Language & Virtual Machine Specifications|
This release continues the evolution of the Platform to ensure the broadest possible success of the core Java technology. It substantially streamlines the footprint of the Platform by removing enterprise APIs, and improves the expressiveness of Java class files.
This document directly specifies API features, enhancements, clarifications, and bug fixes. It also specifies features by reference to other Specifications which are revised in Maintenance Releases of existing JSRs. The specifications of these changes are contained in two accompanying documents: Annex 1 is the complete Java SE 11 API Specification and Annex 2 is an annotated API specification showing the exact differences relative to Java SE 10. Informative background for these changes may be found in the list of approved Change Specification Requests for this release.
This Specification includes the Java SE 11 Editions of The Java Language Specification and The Java Virtual Machine Specification in Annex 3. The Java SE 11 Editions contain all corrections and clarifications made since the Java SE 10 Editions, as well as additions for new features.
Changes to the Java SE Platform Specification are categorized as either features or enhancements. A feature is, roughly speaking, a change of which at least one of the following statements is true:
Any addition that is not a feature is considered an enhancement.
There is, obviously, room for judgment when interpreting this definition. In order to maximize the visibility of Platform revisions we generally tend to consider borderline items to be features rather than enhancements.
Some Component JSR Specifications previously incorporated into the Platform are still available separately or have significant Specifications themselves. Changes to their Specifications are therefore made in separate Maintenance Releases, which are incorporated here by reference:
The javax.transaction.xa package of the following existing component JSR is subsumed by this Specification:
Each Component JSR Specification, or revision thereto, may be related to one or more features in the detailed list below.
|Security||ChaCha20 and Poly1305 Cryptographic Algorithms|
|Key Agreement with Curve25519 and Curve448|
|Transport Layer Security (TLS) 1.3|
|Libraries||Deprecate the Pack200 API|
|HTTP Client (Standard)|
|Remove the Java EE and CORBA Modules|
|Virtual Machine||Dynamic Class-File Constants|
|Nest-Based Access Control|
|Language||Local-Variable Syntax for Lambda Parameters|
Work on features in the Java SE 11 Reference Implementation, which is the Java Development Kit, version 11 (JDK 11), is organized in terms of JDK Enhancement Proposals (JEPs). Each feature description includes a link to the corresponding JEP document as a convenience, but that document is not a normative part of this Specification.
Implement the ChaCha20 and ChaCha20-Poly1305 ciphers as specified in RFC 7539. ChaCha20 is a relatively new stream cipher that can replace the older, insecure RC4 stream cipher.
Implement key agreement using Curve25519 and Curve448 as described in RFC 7748.
Pack200 API in
Define an HTTP Client API that supports HTTP/2 and WebSocket.
Remove the Java EE and CORBA modules from the Java SE Platform and the JDK. These modules were deprecated in Java SE 9 with the declared intent to remove them in a future release.
Extend the Java class-file format to support a new constant-pool form,
CONSTANT_Dynamic. Loading a
CONSTANT_Dynamic will delegate creation
to a bootstrap method, just as linking an
invokedynamic call site
delegates linkage to a bootstrap method.
Introduce nests, an access-control context that aligns with the existing notion of nested types in the Java programming language. Nests allow classes that are logically part of the same code entity, but which are compiled to distinct class files, to access each other's private members without the need for compilers to insert accessibility-broadening bridge methods.
var to be used when declaring the formal parameters of implicitly typed lambda expressions.
A module is a named set of packages designed for reuse. A specification governed by the JCP defines standard packages, and may group them into one or more standard modules.
This Specification groups the standard packages of the Java SE Platform into 21 standard modules, which we refer to as the Java SE modules. The name of a Java SE module always starts with the string "java.". The complete list of such modules is:
Compared to Java SE 10, this Specification adds two modules and removes seven modules. The first new module, java.transaction.xa, contains the javax.transaction.xa package which was subsumed by this Specification as described in the “Component JSR Specifications” section. The second new module, java.net.http, contains the HTTP Client API which was incubated in JDK 9 and 10, then completed in JDK 11 by JEP 321. The seven removed modules are listed in the “APIs removed” section.
The module graph The Java SE modules depend upon each other as stated in their specifications, which are part of the overall API Specification. The corresponding complete Java SE module graph has too many edges to be displayed easily in visual form; here is the transitive reduction of the directed acyclic graph, in which redundant edges are omitted (click to enlarge):
Here is how to read this visualization of the module graph:
If one module depends upon another, and it grants implied readability to that module via a requires transitive directive, then there is an edge from the first module to the second.
At the very bottom is the java.base module, which contains essential classes such as java.lang.Object and java.lang.String. The base module depends upon no module, and every other module depends upon the base module.
At the top is the java.se module, which gathers together all of the modules that comprise the Java SE Platform. This is an example of an aggregator module, which logically gathers the content of other modules by granting implied readability to them, but adds no content of its own. A run-time system configured to contain the java.se module will contain all of the packages of the Java SE Platform.
A module is a Java SE module — that is, considered part of the Java SE Platform Specification — if and only if it is a standard module reachable from the java.se module. The seven modules removed from this Specification are not Java SE modules in the Java SE 11 Platform.
Following the conventions established by the Enhanced Deprecation feature,
various modules and APIs were annotated with
forRemoval=true in the “APIs
Proposed for Removal” section of the Java SE 9
Platform Specification and the Java SE 10
Seven modules that were proposed for removal by the Java SE 9 and 10 Platform Specifications are removed from this Specification. More information about these modules and their APIs is available in JEP 320. Standalone versions of the APIs and their implementations are readily available.
The following individual APIs are removed from this Specification. Many have been deprecated since at least Java SE 1.4 and have been superseded by newer APIs. The number in parentheses indicates the Java SE Platform Specification which first proposed their removal.
The following APIs were proposed for removal by the Java SE 9 or 10 Platform Specifications, and continue to be eligible for removal in a future release. They are not removed from this Specification.
Finally, the following APIs are annotated as
forRemoval=true in this Specification. This makes them
eligible for removal in a future release of the Platform.
The following non-API feature was removed.
SNMP Support Monitoring and management of the Java Virtual Machine is supported primarily by JMX, but also, since Java SE 5.0, by SNMP. However, developer interest in SNMP has been low, and no longer justifies SNMP support in the Java SE Platform. Consequently, this Specification removes the SNMP Management Information Base (MIB) defined for the JVM by JSR 174. (JDK 5.0 implemented an SNMP agent to publish the MIB. The SNMP agent was included in the JDK until its removal in JDK 11.)