You can specify environment variables in a run configuration. These variables then apply only when running your application. You can either specify that the configuration uses the variables as set in the project's properties or specify other variables
To specify environment variables to use at run time:
This opens the Run Configurations dialog box.
This creates a new run configuration for your application.
If you specify a variable which is also specified in the project's properties, the value specified in the run configuration overrides the value specified in the project's properties.
Or:
The configuration inherits the variables specified at project level in the following order - from the build configuration settings, or if there are no variables set in the build configuration settings, then the ones specified in the project's settings.