collections Archives - Page 12 of 12

How to convert int[] to Integer[] in Java?

I’m new to Java and very confused. I have a large dataset of length 4 int and I want to count the number of times ...

April 6, 2022
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Change priorityQueue to max priorityqueue

How about like this: PriorityQueue<Integer> queue = new PriorityQueue<>(10, Collections.reverseOrder()); queue.offer(1); queue.offer(2); queue.offer(3); //... Integer val = null; while( (val = queue.poll()) != ...

April 6, 2022
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Collections.emptyMap() vs new HashMap()

April 6, 2022
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Sort a Map by values

I am relatively new to Java, and often find that I need to sort a Map<Key, Value> on the values. Since the values ...

April 6, 2022
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Why is a ConcurrentModificationException thrown and how to debug it

This is not a synchronization problem. This will occur if the underlying collection that is being iterated over is modified by anything other ...

April 3, 2022
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How to sort a HashSet?

April 3, 2022
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Union or intersection of Java Sets

The simplest one-line solution is this: set1.addAll(set2); // Union set1.retainAll(set2); // Intersection The above solution is destructive, meaning that contents of the original ...

April 3, 2022
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