Java 5 introduced an for-each loop, which is called a enhanced for each loop. It is used to iterate over elements of an array and the collection.
for-each loop is a shortcut version of for-loop which skips the need to get the iterator and loop over iterator using it’s hasNext() and next() method.
1. Java for-each loop syntax
The general syntax for a for-each loop is as follows:
for(T element : a_collection_or_an_array_of_type_T)
{
// This code will be executed once for each element in the collection/array.
// Each time this code is executed, the element variable holds the reference
// of the current element in the collection/array
}
2. Java for-each loop example – iterate over array
For example, following snippet of code prints all elements of an integer array numArray.
int[] numArray = {10, 20, 30, 40};
for(int num : numArray)
{
System.out.println(num);
}
Program Output.
10 20 30 40
3. Java for each loop example – iterate over collection
Similarly, for a collection type also, program will be written same.
public static void main(String[] args)
{
List<Integer> numList = new ArrayList<Integer>();
numList.add(10);
numList.add(20);
numList.add(30);
numList.add(40);
//foreach loop
for(int num : numList)
{
System.out.println(num);
}
}
Program Output.
10 20 30 40
4. for each loop with lambda
Since Java 8, we can use lambda expressions as well for a collection type.
Java program to iterate over a list using for each loop and lambda.
public static void main(String[] args)
{
List<Integer> numList = new ArrayList<Integer>();
numList.add(10);
numList.add(20);
numList.add(30);
numList.add(40);
//foreach loop with lambda
numList.forEach( item -> System.out.println(item) );
//Pass function reference
numList.forEach( System.out::println );
}
Program Output.
10 20 30 40
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