HashMap iterating and deleting element

Question

public void execute(HashMap<String,Coordonnee >c)
{
    c.forEach((k,v) -> {
        p = m.getMin(c);
        sky.add(p);
        c.remove(p.getNom());
    });
}

This throws a java.util.ConcurrentModificationException.

How can I fix that ?

https://stackoverflow.com/questions/223918/iterating-through-a-collection-avoiding-concurrentmodificationexception-when-re — Jack Flamp, Mar 09 '18 at 10:57
Googling "java hashmap ConcurrentModificationException" would have really benn faster for you. — luk2302, Mar 09 '18 at 10:58

score 0 · Answer 1 · answered Mar 09 '18 at 10:58

0

Use removeIf function: map.entrySet().removeIf

Use iterator:

Iterator<Object> it = map.keySet().iterator();

while (it.hasNext())
{
   it.next();
   if (something)
       it.remove();
}

answered Mar 09 '18 at 10:58

Guts

748
4
10

i don't have a condition but the min element after getting it i would delete it – user9467051 Mar 10 '18 at 19:20

score 0 · Answer 2 · answered Mar 09 '18 at 10:59

0

you cannot delete an element of the list while looping through it. You should use Iterator for that.

public void execute(HashMap<String,Coordonnee >c)
{
    Iterator cItr = c.iterator();
    while(cItr.hasNext())
    {
        c = cItr.next();
        p = m.getMin(c);
        sky.add(p);
        cItr.remove(p.getNom());
    }
}

answered Mar 09 '18 at 10:59

Hassan Mudassir

191
2
10

remove() in iterator can not be applied (String) ! – user9467051 Mar 10 '18 at 19:17

HashMap iterating and deleting element

2 Answers2