private synchronized Collection<? extends ScalaPlatformProvider> getProviders() {
if (!this.providersValid) {
if (this.providers == null) {
this.providers = Lookup.getDefault().lookupResult(ScalaPlatformProvider.class);
this.providers.addLookupListener (new LookupListener () {
public void resultChanged(LookupEvent ev) {
resetCache (true);
ScalaPlatformManager.this.firePropertyChange(PROP_INSTALLED_PLATFORMS);
}
});