LearnJava | Learn Java the Easy Way | Learning library
kandi X-RAY | LearnJava Summary
kandi X-RAY | LearnJava Summary
Learn Java the Easy Way - Java and Android Source Code Files from the Book and Online Course. Learn Java the Easy Way (2017, No Starch Press) Learn Java the Easy Way - Online Course
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- Override this to create the instance .
- Handler for options select .
- Tries to enter a message .
- Encodes the given string with the given key value .
- Handles a touch event
- Tokenizes a list of bubbles
- Draws the component of the bubble .
- Called when the bubble is drawn .
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LearnJava Examples and Code Snippets
Community Discussions
Trending Discussions on LearnJava
QUESTION
I'm learning how to work with Java Swing for the first time by following a tutorial on YouTube. I have reached the section covering buttons and have been following the code to the T. However, while attempting to test the button so it would print out the word "test" when I'm using the actionPerformed method, my button would not print out the word.
You can find the original code for that test here:
Main.java
...ANSWER
Answered 2022-Jan-08 at 08:42Change:
QUESTION
I am new to Java and learning through a task.
I have tried to create a program but when I input my name it is raising a InputMismatchException exception.
Here is my code:
Name.java
...ANSWER
Answered 2021-Oct-16 at 11:41If I see it correctly and you are just entering your name the problem is the scanning for int to get n. n is an int and the scanner will get your name which is a string which will result in the mismatch exception. Also v1 is unnecessary vector of objects as you know you are only giving it names, you should write the type name so you could later use the properties of Name.
QUESTION
In the below two examples, the behavior of processing a flux stream seems to be different.
Example 1 :
...ANSWER
Answered 2021-Jul-11 at 12:56Why is the Flux consumer in the first example running in a different thread where as the Flux returned by the R2DBC based repository (second example) is processed in the same main thread?
The key understanding here is that any reactive operator can switch threads (or more precisely, schedulers) as it sees fit. While most operators don't switch, time based operators have to, and they'll default to using the parallel scheduler.
In the first example, you're using the delayElements() operator. As it's a time based operator, by default, it switches to the parallel scheduler, which then runs on the parallel executor (and hence the parallel threads that you see in the logs.) Time based schedulers have to switch as the "immediate" scheduler, which would keep your operations on the same thread, isn't capable of time-based scheduling (which is required by the delayElements operator.)
That's not to say you have to use the parallel scheduler if you have a particular reason not to - there's an overload that lets you set it to whatever you like. If you use .delayElements(Duration.ofSeconds(1), Schedulers.boundedElastic()) for example, you'll see your logs will show the bounded elastic threadpool being used.
On the contrary, in your second R2DBC example, there's no operator switching it away from the immediate scheduler. It will just run on the main thread, as you see from the logs.
If you want a deeper understanding of how threading works in reactor, Simon's flight of the Flux talk is well worth a watch: https://m.youtube.com/watch?v=sNgTTcG-fEU - there's also some accompanying blog posts.
QUESTION
I am a Hibernate beginner. I did a couple of simple tutorials and am trying to write a simple shop backend. Everything works as it should, but I am seeing strange things in my unit tests. When I save an entity, then retrieve it using findById(), it seems that I am simply getting the same object I called save() on, without even retrieving actual values from the database:
...ANSWER
Answered 2021-Apr-13 at 13:32Additionaly to comment about first level cache.
If you are extending JpaRepository you can use
repo.saveAndFlush(p);
or
repo.save(p); repo.flush();
to immediately save data in DB.
After it - repo.findById(p.getId()); will return updated data.
QUESTION
**
public class Main {
...ANSWER
Answered 2020-Jun-10 at 08:49I have copy-paste your code, there is no problem. In comment, the output :
QUESTION
Im getting >>> /Library/Java/JavaVirtualMachines/jdk1.8.0_241.jdk/Contents/Home/bin/java Error: A JNI error has occurred, please check your installation and try again Exception in thread "main" java.lang.SecurityException: Prohibited package name: java.streams
...ANSWER
Answered 2020-Apr-10 at 21:30Move your class to the package that is not reserved for the JDK classes. Use Refactor | Move in IntelliJ IDEA. You can't use java.streams normally, try something like com.company.blabla instead.
QUESTION
package com.learnjava;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Stream;
public class EmployeeSortByGroup {
public static void sortEmployeeByGrp(List persons, String[] sortBy){
for(int i=0;i lines = Files.lines(
Paths.get("path to text file containing record")).skip(1).limit(rows);
long lineCount = Files.lines(Paths.get("path to the text file containing record")).skip(1).limit(rows).count();
Person[] persons = new Person[(int) lineCount];
String[] stringArray = lines.toArray(String[]::new);
for (int i=0;i t_arraylist = Arrays.asList(persons);
sortEmployeeByGrp(t_arraylist,sortByStringArr);
Stream.of(persons).forEach(s->System.out.println(s));
} catch (IOException e) {
e.printStackTrace();
}
}
}
//Person class
package com.learnjava;
import java.util.Comparator;
public class Person {
String FirstName;
String LastName;
int age;
String country;
public String getFirstName() {
return FirstName;
}
public void setFirstName(String firstName) {
FirstName = firstName;
}
public String getLastName() {
return LastName;
}
public void setLastName(String lastName) {
LastName = lastName;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
@Override
public String toString() {
return ""+FirstName+"|"+LastName+"|"+age+"|"+country+"";
}
public Person() {
super();
}
public Person(String firstName, String lastName, int age, String country) {
super();
FirstName = firstName;
LastName = lastName;
this.age = age;
this.country = country;
}
}
ANSWER
Answered 2020-Jan-23 at 16:59Build a compound Comparator incrementally using thenComparing(Comparator).
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You can use LearnJava like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the LearnJava component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .
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