Serialization is a concept that allows us to convert the state of a Java object into a certain format so that this Java object can be stored somewhere and then it will be used by another process. Normally, when using Serialization, our Java object will… Read More
When working with Stream in Java, sometime we can have a Stream with datatype of a List, Set or Array of object. For example:
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List<String> students1 = new ArrayList<>(); students1.add("Khanh"); List<String> students2 = new ArrayList<>(); students2.add("Thanh"); students2.add("Dung"); List<List<String>> students = Arrays.asList(students1, students2); Stream<List<String>> stream = students.stream(); |
Here, we have List of List of String object and when convert into Stream object, we have Stream of List… Read More
To filter a Map using Stream and Lambda Expression in Java, we will use the filter() method of Stream object which will be retrieved from Entry object of Map object with Lambda Expression as filter a List. How is it in details? Let learn together in… Read More
In this tutorial, I will show you how to order elements in a Map object using the Stream object and the Collectors object in Java by key and by value. For example, we have a Map object like this:
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Map<String, Integer> studentMap = new HashMap<>(); studentMap.put("Khanh", 31); studentMap.put("Thanh", 25); studentMap.put("Dung", 35); |
Prior to Java 8, to… Read More
Stream is a new Java object, was introduced from Java 8. It helps us can manipulate on collections and arrays easier and more efficient. So what is it? In this article, I will introduce with you all about the Stream in Java. First, consider the… Read More
Since Java 8, we have ability to convert an object into another type by using map() method of Stream object with Lambda Expression. In this tutorial, I will show to you all some examples about it. Note that, map() method is an intermediate operation in… Read More
Normally, before Java 8, when we want to filter a List, we will iterate through the List and base on the condition we want to filter, we can have a new List on demand. For example, I have a List containing some student names as… Read More
Normally, before Java 8, when we want to sort a List object, we will use Comparator object. For example:
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package com.huongdanjava.javaexample; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; public class Example { public static void main(String[] args) { List<String> names = new ArrayList<>(); names.add("Thanh"); names.add("Khanh"); names.add("Tan"); Collections.sort(names, new Comparator<String>() { @Override public int compare(String s1, String s2) { return s1.compareTo(s2); } }); for (String s : names) { System.out.println(s); } } } |
Result: Since Java 8, we have another way to do the sorting a List object. That is: using sort() method in List object with Lambda… Read More
In this tutorial, I will show you all how using Lambda Expression to foreach a Map object in Java. OK, let’s get started! Same like List object, the forEach () method is also added to the Map object since Java 8, which gives us more… Read More
In this tutorial, I will show you all how using Lambda Expression to foreach a List object in Java. OK, let’s get started! Usually from Java 7 and earlier, whenever you want to print out elements in a List object, for example:
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List<String> names = new ArrayList<>(); names.add("Khanh"); names.add("Tan"); names.add("Thanh"); |
We usually… Read More
