Initialization of org.sat4j.minisat.core.Solver calls Runtime.getRuntime().freeMemory()
The class Solver in the sat4j core package initializes a variable called "memoryTimer" with an anonymous inner class of type ConflictTimerAdapter. This inner class statically initializes a variable called "memorybound":
final long memorybound = Runtime.getRuntime().freeMemory() / 10;
This is an expensive operation which seems to slow down the entire system for counting the available memory. In a multi-threaded scenary with many small partial weighted maxsat instances, it can lead to the machine being occupied with calculating the free memory again and again.
And: The initial class is not necessarily needed at all, e.g. when running a WeightedMaxSatDecorator with the default solver:
maxSatSolver = new WeightedMaxSatDecorator(SolverFactory.newDefault());
I propose to implement another kind of initialization that is only computing the amount of available memory when it is really needed. There are some usages of the variable "solver.memory_based" insat4j-core and sat4j-pb, and I think this could be replaced by a getter method that does the initialization when it is needed.