Mac OS X and Java
MeasureJ2X requires Java to be installed to run. For Mac OS X up to OS X 10.9, Apple's Java 6 was integrally installed as part of the OS X installation.
Mac OS X Maverick (10.9)
Installing or updating to Mac OS X Maverick (10.9) may remove Java from your system. If it has been removed, download and install Apple's Java release  before installing MeasureJ2X.