Source of article: Internet Author: supertoto (translation)/CSDN.Net
By the end of 2003, the beta version of J2SE1.5 will be released. This release and the two updates 1.4.1 and 1.4.2 of J2SE 1.4 that have been released now are released as expected at the 2003 JavaOne conference. If you did not attend this conference, or would like to revisit it, here is a brief summary of the conference.
J2SE 1.4.1 and 1.4.2 Releases
When 1.4.1 (codename "Hopper") was released in September 2002 and its follow-up version 1.4.2 (codename "Mantis") was released as scheduled in January 2003, more than 4,000 bugs had been fixed. , and repairs are still ongoing.
Among the new features of J2SE1.5, some long-awaited features will be added, such as full support for Itenium CPU; Swing users will see two new built-in Look & Feels, one is Windows XP style and the other is GTK style; at the same time, the startup time has also been improved.
Enhancements on the server side mainly include two new GCs, a concurrent mark and sweep algorithm and a parallel young space collector. These two new GCs can be called with compile parameters: -XX:+UseConcMarkSweepGC and -XX:+UseParallelGC.
Next, how to use these parameters to adjust the best performance of the system is what we need to learn and understand in J2SE1.5.
J2SE 1.5 Release
J2SE 1.5 (development codename "Tiger") is an important modification to the Java platform and language. It currently mainly includes 15 JSR requests and other similar updates. This release focuses on several key themes: mainly quality, monitoring and management, performance and scalability, easy development, and desktop clients.
Ease of Development
You may have heard about changes to the Java language that are being made to ease development. This time J2SE implements the following JSRs according to JSR requirements: JSR 201 contains 4 modifications; the core of JSR 175 is to support metadata, while JSR 14 standardizes generics.
Metadata capabilities provide declarative development and replace the code generation and maintenance functions of some tools. Generics improve code reuse without manual casting, which usually brings some problems with type safety.
The other four modifications are:
Use a for loop to traverse a container (Collection type) without explicitly declaring the container's iterator (Iterator);
Enumeration types provide enhanced type safety beyond similar final static int;
Provides autoboxing function when using Primitive Types in generics (primitive types cannot be used in original generics);
Introduced the static constants class to improve explicit sharing of static data;
In addition to the language modifications, there are some additional things to achieve easy development. For example, some people who miss the printf function will find it back; a new concurrency tool (mentioned in JSR 166) will make many more Thread programming becomes simpler and easier.
Scalability and Performance
J2SE version 1.5 promises improvements in scalability and performance, especially in startup time and memory footprint, allowing users to publish an application as quickly as possible. From JSR 163, built-in performance engineering (Performance ergonomics) and a powerful API profile tool will be implemented.
Monitoring and Manageability
Monitoring and management is a major feature in Tiger. Developers who use JMX on J2EE platforms will be very happy to see that such features can be implemented in J2SE. Monitoring of the JVM will allow a complete check of the health of a published application, including monitoring of underlying memory leak detection, error handling and even API stack traces.
Core XML Support
The introduction of J2SE 1.5 has been modified as the core platform for XML, indicating that Java's core API will include XML1.1, SAX 2.0 and DOM Level3. Web service APIs, JAX-RPC, and JAXB will continue to appear in the Web Service package, and these APIs will be added to the core API in future versions.
Desktop Client
The last key new feature is the desktop client. This will bring several new built-in Look & Feels support, as well as enhanced support for skins. In addition to boot speed and memory footprint enhancements, desktop developers have several new features to look forward to.
Unicode 3.1 Support (support for Unicode 3.1)
32-bit surrogate character support will be added cautiously in new versions, so version 1.5 will still use the 16-bit char type.
New IO Support
The new version will provide support for asynchronous IO and enable deeper use of these APIs where appropriate in the platform.
With J2SE 1.4.2 and J2SE1.5, Java developers will have an exciting year ahead.