Launching *Mathematica* is a key task of the Wolfram *Workbench*.
This can be done in run or debug modes by
launching from a notebook .nb file as demonstrated below.

When
*Mathematica* is launched through the notebook front end,
the default kernel for the notebook .nb file is used. If no special
kernel is set for a notebook document, then the default for the
notebook front end will be used.

A run mode launches *Mathematica* in a normal fashion, allowing
execution of code in a fully optimized and efficient manner.

A debug mode launches *Mathematica* in a special way
that allows inspection of the state of a computation as it runs.
The code is not executed in a fully optimized and efficient manner.

Typically you use a debug mode to develop *Mathematica*
code. It can then be deployed and executed. This section describes
issues for launching *Mathematica* in either mode.

Remember that if you want to open a notebook to run your code
you do not need to carry out this launch procedure. This is
because when a notebook is opened, *Mathematica* is
configured to set its path to find your code.
However, a number of other tasks do need a full launch. These include
carrying out a debug session,
running a test file, or
carrying out a
*J/Link* launch.