// returns null if we don't have anything free
private static synchronized Class getFreeVMImplClass() {
while (!freeVMClasses.isEmpty()) {
SoftReference ref = (SoftReference) freeVMClasses.remove(0);
Object o = ref.get();
if (o != null) {
if (DEBUG) {
System.out.println("re-using loaded VirtualMachineImpl");
}
return (Class) o;
}
}
return null;
}
private ObjectMapper mapper() {
if (mapperRef == null) {
mapperRef = new SoftReference<ObjectMapper>(new ObjectMapper());
}
ObjectMapper mapper = mapperRef.get();
if (mapper == null) {
mapper = new ObjectMapper();
mapperRef = new SoftReference<ObjectMapper>(mapper);
}
return mapper;
}