Java SE Mobile Profile

[John Platts]

Here are the reasons why a Java SE Mobile Profile is really needed:
- Java ME does not support all of the Java SE 5, 6, and 7 language features.
- Even though the Android platform is not a Java SE or Java ME implementation, the Android platform supports Java SE 5 and 6 language features plus API's found in Java SE 5 and 6 but missing in Java ME.
- Some Java ME implementations do not comply with the Java SE 5 or later memory model. Requiring support for the Java SE 5 and later memory model will improve portability of mobile applications to both desktop platforms and other mobile platforms. Furthermore, many mobile devices use processors that are not based on the x86 architecture, and requiring support for the Java SE 5 and later memory model will improve consistency across mobile platforms since some of these devices have processors that require memory barriers to ensure correctness of volatile reads, volatile writes, and synchronization.
- Some of the Java SE 5 and later core API's are not available on Java ME platforms, although implementations of many of the Java SE 5, 6, and 7 core API's are usable on mobile platforms.
- Porting Java-based applications to mobile platforms is not always easy because Java ME lacks language features and API's available in Java SE 5 and later.
- Supporting the Java SE Concurrency Utilities API (JSR 166) on mobile platforms improves portability, performance, and thread safety.
- Some of the JVM programming languages are dependent on features not available on the Java ME platform. Adding support for API's that these programming languages depend upon will enable mobile applications to be developed in other programming languages. One of the API's that would be provided in the Java SE Mobile Profile is support for JSR 292, which provides support for dynamically typed languages on the Java SE platform.
- The standard profile of Java SE has a lot of classes that are currently required by the Java SE specification, but providing a mobile profile that does not require the implementation of all of the classes required by the Java SE standard profile will reduce the footprint while retaining compatibility and portability. Java SE Mobile Profile implementations must implement all of the classes and methods required by the Java SE Mobile Profile specification.
- Advances in mobile device technology allow for a footprint that is larger than the Java ME implementation. These mobile devices can take advantage of a Java SE Mobile Profile implementation, which has a smaller footprint than a typical Java SE implementation.

Here are the goals of the Java SE Mobile Profile:
- Provide a smaller footprint for mobile devices
- Support all Java SE 5, 6, and 7 language features
- Provide support for a subset of the Java SE 6 and 7 API's on mobile platform
- Improve competition against Android-based devices, Apple iOS-based devices, and Microsoft Windows Mobile devices
- Ease porting of Android-based and Java ME-based applications to the Java SE Mobile Profile
- Improve portability of Java SE applications to mobile platforms
- Make it easier to develop Java-based applications for mobile platforms
- Make it easier to share code with both mobile platforms and desktop platforms (at both the binary and source code levels)
- Support a mobile version of the NetBeans platform on the Java SE Mobile Profile. There is already a mobile version of the Eclipse Platform called eRCP, but eRCP is based on Java ME plus the Eclipse eSWT API. NetBeans Platform 6.9 and later is dependent on Java SE 6 APIs and language features. The Java SE Mobile Profile will make it possible to support a mobile version of the NetBeans platform.

Here is a list of some of the packages that would be part of the Java SE Mobile Profile:
- java.applet
- java.awt
- java.awt.color
- java.awt.datatransfer
- java.awt.event
- java.awt.font
- java.awt.geom
- java.awt.im
- java.awt.image
- java.beans
- java.dyn
- java.io
- java.lang
- java.lang.ref
- java.lang.reflect
- java.math
- java.net
- java.nio.channels
- java.nio.channels.spi
- java.nio.charset
- java.nio.charset.spi
- java.nio.file
- java.nio.file.attribute
- java.nio.file.spi
- java.rmi
- java.rmi.registry
- java.security
- java.security.acl
- java.security.cert
- java.security.interfaces
- java.security.spec
- java.sql
- java.text
- java.util
- java.util.concurrent
- java.util.concurrent.atomic
- java.util.concurrent.locks
- java.util.jar
- java.util.zip
- javax.imageio
- javax.imageio.event
- javax.imageio.metadata
- javax.imageio.stream
- javax.security.auth.x500
- javax.sql
- javax.swing
- javax.swing.border
- javax.swing.event
- javax.swing.plaf
- javax.swing.table
- javax.swing.text
- javax.swing.tree
- javax.swing.undo

A Java SE Mobile Profile implementation could be provided by adapting the OpenJDK7 class library and removing classes that are not needed on mobile devices. A VM implementation could be provided by either optimizing the HotSpot VM found in OpenJDK 7 to minimize the footprint and provide performance on mobile devices, or modifying the phoneME VM to support Java SE 5, 6, and 7 features and the Java SE mobile profile. JVM implementations targeting the Java SE mobile profile can be easily retargeted to support the Java SE standard profile in the following use cases:
- Netbooks
- Virtualized servers
- Virtualized desktops