Question

I have encountered a problem i cannot find a solution.
I am using a HashSet to store values. The values I store is of the custom type Cycles where i have overridden the HashCode and equals as following in order to make sure the slow performance is not cuased by the hascode or the equal methods
Also i have set the initial capacity of the hashset to 10.000.000

@Override
public int hashCode() {
 final int prime = 31;
 int result = 1;
 result = prime * result + (int) (cycleId ^ (cycleId >>> 32));
 return result;
}

@Override
public boolean equals(Object obj) {
 if (this == obj)
 return true;
 if (obj == null)
 return false;
 if (getClass() != obj.getClass())
 return false;
 Cycle other = (Cycle) obj;
 if (cycleId != other.cycleId)
 return false;
 return true;
}

After the first 1.500.000 first values when i try to add a new value (with the add method of the HashSet class) the program is very slow. Eventually i am going to have java out of memory exception (Exception in thread “Thread-0” java.lang.OutOfMemoryError: Java heap space) before the stored values reach the 1.600.000

The IDE i use is Eclipse. So the next step was to increase the JVM heap size from the default value to 1 giga (using the commnads Xmx1000M and Xms1000M)
Now the elipse starts with 10 times more memory available (i can see that in the bottom right where the total heap size memory and used memory is shown) but again i have the same “slow” performance and the same out of memory error IN THE SAME VALUES as before (after the 1.500.000 and before 1.600.000) which is very odd.

Does anyone has an idea what it might be the problem?

Thank you in advance

Answer 1

You don’t want to increase the JVM heap for Eclipse, you want to set it for your program.

Go to Run > Run Configurations (or Debug Configurations) and set the VM Options there.