add plots for percentiles

pdb-api/src/test/java/org/lucares/memory/MemoryScale.java

@@ -25,6 +25,7 @@ public class MemoryScale {
 		runGc();
 		long memoryAfter = getUsedMemory();
 		System.out.println("used memory: " + (memoryAfter - memoryBefore));
+		handle.hashCode(); // use the variable, so causes no warnings and is not removed by JIT compiler
 	}
 	
 	private static Object createObject(){