Oracle® Java ME Embedded

Table of Contents

• Introduction

• What's Supported in This Release

• Usage Notes

• Installation and Runtime Security Guidelines

• Known Bugs

• Product Documentation

• Documentation Accessibility

Introduction

The Oracle Java ME Embedded release 8.1 software for the Raspberry Pi platform is a ready-to-run binary for use with an off-the-shelf Raspberry Pi Model B board. The Oracle Java ME Embedded release 8.1 software underwent sanity check for use with a Raspberry Pi Model B+ board. See the Usage Notes for more details.

The Oracle Java ME Embedded software uses an optimized platform stack for small embedded devices, which includes the Connected Limited Device Configuration (CLDC) HotSpot Implementation (Java Virtual Machine) version 8, the Micro Edition Embedded Profile (MEEP) application environment, the Generic Connection Framework (GCF) API, and enhanced support for various Java Specification Requests (JSRs).

What's Supported in This Release

The following features are included in the Oracle Java ME Embedded software:

• CLDC 8

  • Full API set

• General Connection Framework (GCF) 8

  • File protocol (file: scheme)

  • Datagram (datagram: scheme)

  • TCP/IP client socket (socket: scheme)

  • TCP/IP server socket (socket: scheme)

  • Secure client socket (ssl: scheme)

  • HTTP (http: scheme)

  • HTTPS (https: scheme)

  • Secure datagram (dtls: scheme)

  • Secure server socket (ssl: scheme)

  • Access points

  • The NetworkUtilities class

  • javax.microedition.pki package and other security-related enhancements

  • TLS v1, v1.1, v1.2

• Java ME Embedded Profile (MEEP) 8:

  • javax.microedition.event

  • javax.microedition.power

  • javax.microedition.io (IMC, PushRegistry)

  • javax.microedition.midlet

  • javax.microedition.rms

  • javax.microedition.swm

• Device I/O APIs, which provide enhanced device controls and improved input/output (I/O) for small embedded devices:

  • GPIO

  • I2C

  • Serial Peripheral Interface (SPI)

  • Universal Asynchronous Receiver/Transmitter (UART)

  • Watchdog Timer

  • Modem Control (AT) command set

  • ATDevice, which is a simple AT commands-based device on the EmbeddedDevice1 emulator that responds with OK to any command. It has the following configuration:

    • Device Name: EMUL, ID: 13, Device Number: 1, Hardware Channel's Number: 1

• Ongoing support for the following optional packages:

  • JSR 75 - (FileConnection API only)

  • JSR 172 - Web Services

  • JSR 177 - Security and Trust Services API (SATSA-CRYPTO package only)

  • JSR 179 - Location

  • JSR 280 - XML API for Java ME

• Tooling includes:

  • Command-line interface (CLI)

  • Logging

  • File system commands

  • Debugging

• Memory monitoring is fully supported in this release and provides:

  • Contents of the Java heap

  • A call context for each object at its creation

• CPU profiling is fully enabled in this release and provides:

  • A way to identify bottlenecks in applications

  • The following data for each method: an execution duration, exact number of calls, and a method context

• Network monitoring support

Usage Notes

The Oracle Java ME Embedded software for the reference board platform includes an CLDC implementation with a high-performance Java Virtual Machine that can run IMlets and access input/output ports. This runtime is optimized for the reference board platform.

Getting Started Guide for the Reference Platform (Raspberry Pi) describes how to install the Raspbian distribution on the SD card, how to connect to the board from the development host computer, and how to install, run, and debug IMlets on the board.

Note the following important information before running the Oracle Java ME Embedded software on the board:

• This release does not support running multiple instances of its executable; avoid simultaneously starting several instances of any of scripts or executable files, regardless of whether these are from the same installation of the software or from different installations. The software can run multiple IMlets in the same instance of a virtual machine; you do not need to start multiple VMs to run several applications at a time. Not following this precaution can result in malfunctions with uninformative error messages and might cause corruption of the installation files.

• All devices, except MMIO, support only the exclusive mode. MMIO also supports the shared access mode.

• No generic device is implemented, as would be accessed using the package jdk.dio.generic.

• The jdk.dio.power package does not support the actual hardware power state switch.

• Access points are one-to-one mapped to network interfaces. However, the access point management functionality is implemented with a limitation which does not allow to change the state of the Linux network interface from Java. The state can only be read. The proxy setting is also available through an environment variable.

• System events and power management are not implemented due to lack of support on the Raspbian side.

• On Raspberry Pi Model B+, only the same I/O pins as in Model B are fully supported. Additional pins can be used at own risk.

Installation and Runtime Security Guidelines

The Oracle Java ME Embedded release 8 software installation requires an execution model that ensures certain networked resources available. These required resources might include, but are not limited to, a variety of communication capabilities between the product's installed components.

It is important to note that the product's installation and runtime system is fundamentally a developer system that is not specifically designed to guard against malicious attacks from outside intruders. Given this, the product's architecture can present an insecure operating environment to the installation file system and its runtime environment, during execution. For this reason, it is critically important to observe the precautions outlined in the following security guidelines when installing and running the software.

To maintain optimum network security, the software package can be installed and run in a closed network operating environment; the software system is not connected directly to the Internet or to a company intranet environment that could introduce unwanted exposure to malicious intrusion. This is the ideal secure operating environment whenever the application under development does not require an Internet connection.

An example of a requirement for an Internet connection is when the system must communicate with a wireless network over the Internet to fully execute the application under development. Whether or not an Internet connection is required depends on the particular Java ME application running in the development environment. For example, some Java ME applications can use an HTTP connection. If the environment is open to network access, you must observe the following precautions to protect valuable resources from malicious intrusion:

• Locate the development environment behind a secure firewall that strictly limits unauthorized network access to its file system and services. Limit access privileges to those that are required for development while allowing all the bidirectional local network communications that are necessary for the application's functionality. The firewall configuration must support these requirements to run the software while also addressing them from a security standpoint.

• Follow the principle of least privilege by assigning the minimum set of system access permissions required for installation and execution of the software.

• Do not store any sensitive information on the same file system that hosts the installation.

• To maintain the maximum level of security, ensure that the operating system patches are up-to-date on host machines in the development environment.

Known Bugs

For generic bugs in this release of the Oracle Java ME SDK that might affect the Raspberry Pi platform, see Oracle Java ME Software Development Kit Release Notes.

The following are known bugs in this release of the Oracle Java ME Embedded software:

• A debugging session in NetBeans does not start for an application with the following breakpoint: Exception Class Name is java.lang.RuntimeException, Stop On: Caught.

• CLI: the get command produces an incorrect output in the case when it cannot write to a file: <<get,FAIL,Illegal char <>> instead of <<get,FAIL,unable to write into file ...>>.

• The KeyPairGenerator.generateKeyPair() method causes a VM restart.

• When an application runs right after the Raspberry Pi board re-boot, the method UART.read(ByteBuffer) looses one byte written by the UART.read(ByteBuffer) method. This issue disappears at the next application run.

Product Documentation

The following documentation is included with this release of the Oracle Java ME Embedded software. See http://docs.oracle.com/javame/.

Documentation Accessibility

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Access to Oracle Support

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