JSRs Now Available for Java SE 7 and Java SE 8
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Mark Reinhold has announced the availability of four new JSRs, two of which deal with the implementation of Plan B, the future versions of Java.
JSR 337: Java SE 8 Release Contents, for the eventual JDK 8 (the rest of Plan B).
The following is a brief summary of what is included in each of the specifications:
JSR 336 - Java SE 7 Release Contents
The specification focusses on four main themes: productivity, performance, universality and integration. Productivity is addressed with the addition of automatic management of I/O resources, simpler generics and more concise exception handling.
Performance will be covered with the addition of new concurrency APIs from Doug Lea, including a Fork/Join framework. The invokedynamic instruction will provide universality, improving the performance of dynamic languages, and the new Filesystem API (JSR 203) will cover integration with native filesystems, while also allowing the same portable access to file operations.
There are also some smaller features planned for inclusion such as Heavyweight/lightweight component mixing, translucent and shaped windows, JDBC 4.1 and thread-safe concurrent class loaders.
JSR 337 - Java SE 8 Release Contents
The rest of Plan B, Java SE 8 covers the three themes of productivity, performance and modularity. The Collections framework is to be extended with literal expressions for immutable lists, sets and maps. Collections will also be enhanced to work better on multicore processors, supporting bulk-data operations such as filter, map and reduce.
JSR 308 is also proposed to be included which would allow annotations to be placed on any occurance of a type.
The much discussed module system is also included in this JSR, with the aim to save Java developers from "classpath hell".
JSR 334 - Small Enhancements to the Java Programming Language
This JSR currently covers the six following language changes:
- Strings in switch statements
- Binary integral literals and underscores in numeric literals
- Multi-catch and more precise throw
- Improved Type Inference for Generic Instance Creation
- try-with-resources statement
- Simplified varargs method invocation
JSR 335 - Lambda Expressions for the Java Programming Language
Support for closures. This will include the addition of
- Lambda expressions
- SAM conversion
- Method references
- Virtual extension methods
Meanwhile, Stephen Colebourne has provided some analysis of the licence behind the JSRs, particularly focussing on how the TCK licence is expressed.
To be honest, I'm surprised that the TCK license for Java SE 7 still contains any pretence that it can be implemented in open source by anyone other than Oracle. At least the restrictions are clear (and I suspect, but cannot prove, that very similar restrictions were offered for Java SE 5 in the Sun/Oracle vs Harmony dispute).
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