... Loop Through a HashSet. This was the default approach in Java 1.4 and older versions. In Java 8 and above, we can loop over a set with the help of streams, lambdas and forEach as shown below – Iterate over a HashSet using iterator() and Java 8 forEachRemaining() method. Fetch the Iterator from a HashSet object use its member function iterator() i.e. Although the following example uses Generics, so you need Java 1.5 + to execute it. This Java Example shows how to iterate through elements Java HashSet object. 3. Iterate over a HashSet using iterator(). The following example shows different ways of iterating over a HashSet. 8 Best ways to Iterate through HashMap in Java Method 1. Iterate over a HashSet using Java 8 forEach and lambda expression. By calling iterator() method, you can get Iterator object. entrySet() returns a Set and a Set interface which extends the Collection interface and now on top of it, we can use the Iterator. Iterate through HashMap using Iterator. Java HashSet. Below example shows how to read all elements from the HashSet objects. You can get the iterator by calling the iterator() method of the Set interface. A HashSet is a collection of items where every item is unique, and it is found in the java.util package: Example. To loop through elements in a HashSet, use for loop as following: public void postNumbers(HashSet uniqueNumbers) { for (String n : uniqueNumbers) { System.out.println(n); } } To iterate over a HashSet we will use an Underlying Iterator object of the HashSet. Iterate through a HashMap EntrySet using Iterator Map interface didn’t extend a Collection interface and hence it will not have its own iterator. You can iterate a HashSet by using either forEach(Consumer), since Java 8, or for-each loop, Iterator, and SplitIterator The iteration order is unpredictable as HashSet has no guarantee to it Index-loops such as for-index, while-index, do-while-index cannot be used to iterate a HashSet … In our code, we first import the HashSet and Iterator libraries from java.util. Iterating over a HashSet. Iterating over this set requires time proportional to the sum of the HashSet instance's size (the number of elements) plus the "capacity" of the backing HashMap instance (the number of buckets). First option to iterate a HashSet in Java is to use a ForEach loop, if you are just iterating without doing any structural modification (adding or removing element) to the Set then this is the best option to iterate a HashSet. Download Run Code. Thus, it's very important not to set the initial capacity too high (or the load … Java 8 – Converting Set to Streams. In this article we will discuss how to Iterate over a HashSet in Java using HashSet. Fetch Iterator from HashSet. Loop through the items of an HashSet with a for-each loop: Example for (String i : cars) { System.out.println(i); } You can iterate through HashSet by getting Iterator object. Iterate over a HashSet using simple for-each loop. Next, we initialize a HashSet called fruits and assign it three values: Pear, Grapefruit, and Mango. Using iterator() method which returns an iterator over the elements in the given Set. HashSet does not order its elements, thus referring to specific index does not work. This method uses java.util.Iterator to go through the HashMap. Then we declare a class called RetrieveFruits in which the code for our program is located. Since Set interface or HashSet class doesn't provide a get() method to retrieve elements, the only way to take out elements from a Set is to iterate over it by using the Iterator, or loop over Set using advanced for loop of Java 5. 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