Set<String> set = new TreeSet<>(); set.add("2"); set.add("1"); set.add("3"); String first = set.stream().findFirst().get(); This will help you retrieve the first element of the list or set. Given that the set or list is not empty ( get() on empty optional will throw java.util.NoSuchElementException )
We can retrieve the first element in a Set using an Iterator. The Set interface allows us to get an Iterator for all implementations using the iterator () method. We can then call next () on the Iterator to get the first item: @Test void givenASet_whenUsingIterator_thenRetrieveAnItem() {.
As, you mentioned pContext.getParent().getPropertyValue return Set. You can convert Set to List to get the first element. Just change your code like: Set<String> siteIdSet = (Set<String>) pContext.getParent().getPropertyValue(..); List<String> siteIdList=new ArrayList<>(siteIdSet); String firstItem=siteIdList.get(0);
In Java, we can use Set.iterator().next() to get the first item from a java.util.Set. import java.util.HashSet; import java.util.Set; public class JavaExample {. public static void main(String[] args) {. Set<String> examples = new HashSet <>(); examples.add( "1" ); examples.add( "2" ); examples.add( "3" );
Getting the First Item from a Java Set Java Sets are useful for storing unique elements, and you may often need to retrieve the first item from a Set. In this, we’ll explore two common methods to achieve this: using an iterator and using a stream.
To get the first element of a List or Set in Java, you can use the following methods: List: List<String> list = new ArrayList <>(); // add elements to the list String first = list.get( 0 ); Note that this will throw an IndexOutOfBoundsException if the list is empty. Set: Set<String> set = new HashSet <>();
2.1. Iterator. The most basic and close-to-metal method of iterating over the set is invoking the iterator method exposed by every Set: Set<String> names = Sets.newHashSet( "Tom", "Jane", "Karen" ); Iterator<String> namesIterator = names.iterator(); Then we can use the obtained iterator to get elements of that Set, one by one.
To find first element in a HashSet, we can use findFirst () method of Stream API which returns Optional<T> and. We can invoke get () method on Optional<T> to obtain the final result. Similarly, to get last element from HashSet, we can use reduce () method of Stream API which returns Optional<T> and.
Interface Set<E>. A collection that contains no duplicate elements. More formally, sets contain no pair of elements e1 and e2 such that e1.equals(e2), and at most one null element. As implied by its name, this interface models the mathematical set abstraction. The Set interface places additional stipulations, beyond those inherited from the
This tutorial explains you how to find first element from collection like List or Set using Java 8 streams findFirst (), iterator () and listIterator methods. Find first element from List or Set. The below example shows how to get first element of List or Set using different methods of List or Set. package com.Sneppets.app;