This code:

ProjectClassPathExtender pce =
project.getLookup().lookup(ProjectClassPathExtender.class);
ProjectClassPathModifierImplementation pcm =
project.getLookup().lookup(ProjectClassPathModifierImplementation.class);
if (pcm != null) {
    for (String type : classPathTypes) {
        ProjectClassPathModifier.addLibraries(new Library[] { swdpLibrary },
sourceRoot, type);
    }
} else if (pce != null) {
    pce.addLibrary(swdpLibrary);
} else{
    throw new IllegalStateException("Current project does not have support " +
            "for ProjectClassPathModifier or ProjectClassPathExtender");
}

can simply be replaced with

for (String type : classPathTypes) {
    ProjectClassPathModifier.addLibraries(new Library[] { swdpLibrary },
sourceRoot, type);
}

PCPM.aL already checks for both PCPMI and PCPE in lookup and insulates client
code from future SPI changes.