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Execution Environment Descriptions

Revision as of 16:17, 12 February 2008 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.

Variable Substitution

The launcher does not perform arbitrary variable substitution. However, in the context of the .ee file, it will replace ${ee.home} with the directory containing the .ee file. Example:


This is useful for vm arguments that require absolute paths. For example, some vms may require a property like java.home to be set with an absolute path, this would normally be set by the java.exe, but when starting using the JNI invocation API, the property would need to be set in the .ee file.

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.src Source archive(s) for class libraries. Each entry is applied to its corresponding boot class path entry (based on order). When there are more boot class path entries than source entries, the last source entry is applied to remaining boot class path entries. x
ee.javadoc Javadoc location for class libraries. Must be a URL. You can use ${ee.home} and '..' segments to specify a file location relative to the ee file. x
ee.ext.dirs x
ee.endorsed.dirs x
ee.additional.dirs x
ee.language.level 1.4, 1.5 x
ee.class.library.level J2SE1.4, CLDC, Foundation 1.0. These match osgi define execution environments x J2SE1.4[jit,gc_pol] First segment matches osgi defined execution environments, second segment lists properties for the vm that could be selected upon. x
<arbitrary vm args> arguments passed through to vm
java.home The root install directory of the runtime environment or development kit. Corresponds to a value that could be used for JAVA_HOME environment variable. x
ee.debug.args The arguments to use to launch the VM in debug mode. For example "-agentlib:jdwp=transport=dt_socket,suspend=y,address=localhost:${port}". The "${port}" variable will be substituted with a free port at launch time. When unspecified, default arguments are constructed based on the language level of the VM. x
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. x
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. x

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