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
In this tutorial, I will show you all how to convert char to String in Java. Let consider the following example:
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package com.huongdanjava.javaexample; public class Example { public static void main(String[] args) { char c = 'K'; } } |
To convert this character “K” to String, we will use the Character object with method toString() as below:
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package com.huongdanjava.javaexample; public class Example { public static void main(String[] args) { char c = 'K'; String s = Character.toString(c); System.out.println(s); } } |
Result:
In this tutorial, I will show you some ways to create directory in Java. The first solution, we will use the File object. This object allow us can create a specific directory or a specific directory with its child. To create a specific directory, we… Read More
I usually need to convert Array object to List object and vice versa in my company project. So, I write this tutorial to share to you all how I can do that. In this tutorial, I use Array and List object with type of String… Read More
NullPointerException is popular exception in Java programming. Even those who experienced code for many years are also defective. I often troll my colleague in my company that: I see you are very good at code, never face with error, if have, only with NPE (stands… Read More
Lambda Expression was introduced to enable functional programming in Java, help us can remove unnecessary code. So, what is Lambda Expression? In this tutorial, I will introduce to you all some basic knowledges about Lambda Expression in Java. OK, let’s go. Why do we need… Read More
