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Execution Environment Descriptions

Revision as of 12:22, 10 April 2007 by (Talk | contribs) (EE Properties)

In 3.3M6, the Equinox Launcher introduced the notion of an execution environment description file. This is a file with extension .ee that describes a JVM and the execution environment it represents.

.ee File Format

Entries in the .ee file are arguments to a java vm. Each argument is on a separate line. The arguments in this file should be all the arguments required to configure the virtual machine for the environment the .ee file describes.

Bug 180763 has been raised to allow comments in this file.

Equinox Launcher

The Equinox Launcher in 3.3 can be started with a -vm argument pointing to a .ee file. This file will be read and the arguments will be used when creating the JVM.

The Equinox Launcher defines the following arguments which it expects to find in the .ee file. The following arguments specify the vm and information required by the launcher to start that vm:

  • -Dee.executable=<path to java executable>
This argument specifies the path the java executable the launcher should use to start the virtual machine.
  • -Dee.executable.console=<path to java executable>
This argument specifies the path the java executable the launcher should use to start the virtual machine when a console is desired.
  • -Dee.vm.library=<path to jvm shared library>
This argument specifies the path to a shared library. The equinox launcher will use this library to load the vm in-process using the JNI Invocation API. The launcher looks for the "JNI_CreateJavaVM" symbol in the library.
  • -Dee.library.path=<list of paths>
This arguments specifies a list of paths (separated by ';' or ':' as appropriate for the platform) that are required in order to load the ee.vm.library.
For example, on Linux, this property represents paths that need to be on the LD_LIBRARY_PATH environment variable in order to load the jvm shared library.

In addition to being interpreted by the Equinox Launcher, these arguments are passed to the VM so that they are available in the java process as system properties.


In all of the above arguments, the path used can be either a relative path or an absolute path.

If a relative path is used, it is resolved first relative to the .ee file. If it is not found relative to the .ee file, it is then resolved against the working directory.

If the Equinox Launcher is started with the -vm argument pointing at a directory, then it will first look for a file in that directory. If one is found, it will be used to start the vm as outlined below.

-vm <.ee file>

When the Equinox Launcher is started with the -vm argument pointing at a .ee file (or at a directory containing a file as above), the vm will be started as follows:

  1. ee.vm.library : If this property is defined, the indicated library will be loaded to start the vm using the JNI invocation API. The ee.library.path property will be used on those platforms where it applies.
  2. ee.executable, ee.executable.console: One of the indicated java executables (depending on whether or not a console is desired) will be used to launch the jvm in a separate process.

EE Properties

The following is a list of proposed standard properties that and their current interested parties. Because the .ee file is interpreted as vm arguments, for the properties listed below, the actual entry in the .ee file would be "".

Property Name Example/Description Interested Parties
Eclipse.exe Eclipse JDT Java.exe Java DLL J9 DLL
ee.executable javaw.exe or j9w x x
ee.executable.console java.exe or j9.exe x x
ee.library.path where to find VM libraries x x
ee.vm.library shared library containing JNI entry point x
ee.bootclasspath x
ee.ext.dirs x
ee.endorsed.dirs x
ee.additional.dirs x
ee.language.level 1.4, 1.5 x
ee.class.library.level J2SE1.4, CLDC, Foundation 1.0. These match osgi define execution environments x J2SE1.4[jit,gc_pol] First segment matches osgi defined execution environments, second segment lists properties for the vm that could be selected upon. x
<arbitrary vm args> arguments passed through to vm
ee.home The directory containing the .ee file. Relative paths are relative to this directory. The launcher will set this property, it does not need to be specified in the file.
ee.filename Absolute path to the .ee file, since there could be more than one in the ee.home directory. Also set by the launcher.

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