passed task, but nothing displayed?

There is no guarantee when the JVM will actually do garbage collection. This is all handled internally by some complex algorithm based on how much memory the CPU has, how much memory the program is using, the speed of the CPU, and many other factors. Maybe ten years ago, on a windows XP system, 50000 objects in the computers memory was probably a lot, however today that is quite trivial. Try increasing the amount of objects created to a million, that kicks off the GC on my computer. If that doesn't work try increasing it at 10 million, 100 million, etc. You could alternatively use this inside your object creation loop:

loop() {
   //create ojbects
   System.gc(); // add this
}

This activates the garbage collection, though you should not use this in your code other than for testing/debug purposes, and never have it in final code. It will slow the code down quite a bit