java , Detect a key press in console

Detect a key press in console


Tag: java

I want to execute a certain function when a user presses a key. This will be run in the console, and the code is in Java. How do I do this? I have almost zero knowledge of key presses/keydowns, so I could really use an explanation as well.


If you want to play with the console, you can start with this:

import java.util.Scanner;

public class ScannerTest {

    public static void main(String[] args) {
        Scanner keyboard = new Scanner(;
        boolean exit = false;
        while (!exit) {
            System.out.println("Enter command (quit to exit):");
            String input = keyboard.nextLine();
            if(input != null) {
                System.out.println("Your input is : " + input);
                if ("quit".equals(input)) {
                    System.out.println("Exit programm");
                    exit = true;
                } else if ("x".equals(input)) {
                    //Do something

Simply run ScannerTest and type any text, followed by


Reading and modifying the text from the text file in Java

I am have a project that need to modify some text in the text file. Like BB,BO,BR,BZ,CL,VE-BR I need make it become BB,BO,BZ,CL,VE. and HU, LT, LV, UA, PT-PT/AR become HU, LT, LV, UA,/AR. I have tried to type some code, however the code fail to loop and also,in this...

Javadoc: Do parameter and return need an explicit type description

When Javadoc'ing, I don't know whether you should explicitly say whether the parameters are of type String or int. For example /** * This method does something * @param foo an object of type Foo * @param abc the number of doors, of type int * @return the number of...

@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW) doesn't work

I need to delete a list of employees ignoring any integrity constraints (i.e. successfully delete the entity that doesn't related to any others yet or skip the entity that related to others) using JPA 2.0 and EJB3.0 on glassfish3.0: I iterated on the list and call entity manager in a...

viewResolver with more folders inside of WEB-INF/jsp is not working in spring

<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /> <!-- avoid '???' --> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp"/> </bean> if i create other subfolders under jsp , for instance /WEB-INF/jsp/reports , /WEB-INF/jsp/insertions how should i configure now the viewResolver to can resolve these new sub folders??...

Mysterious claim of a missing { in eclipse

I have a case of a mysterious missing curly brace that I don't see any use for. Eclipse says, "Syntax error on token ";", { expected after this token". Either I am missing something very silly or there is something new I have to learn about Java. This is the...

PropertyNotFoundException in jsp

Am getting this error in my application javax.el.PropertyNotFoundException: Property 'survey_id' not found on type com.moh.forms.MOH731 javax.el.BeanELResolver$BeanProperties.get( javax.el.BeanELResolver$BeanProperties.access$400( javax.el.BeanELResolver.getValue( This is my @Id @GeneratedValue(strategy = GenerationType.AUTO) private int survey_id; public MOH731 (int survey_id, String uname)...

Get the value of the last inserted record

I am trying to get the stop_name of the last inserted row in the table with preparedStatement. How can I get the last inserted one? I appreciate any help. behavoiur table: CREATE TABLE IF NOT EXISTS behaviour( behaviour_id INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY, mac VARCHAR(30) NOT NULL, stop_name VARCHAR(30)...

Finding embeded xpaths in a String

I have a string where I have the user should be able to specify xpaths that will be evaluated at runtime. I was thinking about having a the following way to specify it. String = "Hi my name is (/message/user) how can i help you with (/message/message) "; How can...

How to call MySQL view in Struts2 or Hibernate

I have a view in MySQL database CREATE VIEW CustInfo AS SELECT a.custName, a.custMobile, b.profession, b.companyName, b.annualIncome FROM customer a INNER JOIN cust_proffessional_info b ON a.cust_id=b.cust_id Is there any way that i can call this view using Struts2 or in Hibernate. I have tried to search it but could not...

How to do custom rounding of numbers in Java?

Suppose I want to round numbers that have mantissa greater than 0.3 'up' and those below 'down'. How can I do it in Java? The only thing that came to my mind was Math.round(), but I can't seem to make it follow a certain rule....

custom arraylist get distinct

is there any way to get the distinct values of a custom arraylist? public class mystatistic extends BaseActivity { public String objectid; public String playerid; public String playername; public String enemyid; public String enemyname; public String question; public mystatistik(String objectid, String playerid, String playername, String enemyid, String enemyname, String question)...

Selenium catch popup on close browser

I'm trying to test that when I close my window a popup shows with a warning message. I've tried both driver.close() and driver.quit() after making sure I'm on the proper window but this just terminates the process since my popup doesn't show. I could test it by using the awt...

Android String if-statement

I have a if-statement in the start of my app if (ready.equals("yes")){ ... } and later on my code I have ready="yes"; but the if statement is never called, why? The ready="yes"; is called from a background thread, is that why? public void DownloadFromUrl(final String fileName) { //this is the...

Using world coordinates

I am currently using pixels as units for placing objects within my world, however this can get tedious because I only ever place objects every 16 pixels. For example, I would like to be able to place an object at position 2 and have the object rendered at the pixel...

Get document on some condition in elastic search java API

As I know we can parse document in elastic search, And when we search for a keyword, It will return the document using this code of java API:- searchHits = node.client() .prepareSearch() .setIndices("indices") .setQuery(qb) .setFrom(0).setSize(1000) .addHighlightedField("file.filename") .addHighlightedField("content") .addHighlightedField("meta.title") .setHighlighterPreTags("<span class='badge badge-info'>") .setHighlighterPostTags("</span>") .addFields("*", "_source")...

How to check if an ExecutionResult is empty in Neo4j

I am executing a query in neo4j using java. I don't know how to check if the execution result is empty. Here is my code. String firstquery=" start n=node(*) match(b)-[relatedto]->(n) where b.value=\""+applicationName+"\" return n"; ExecutionResult execResult = execEngine.execute(firstquery); System.out.println("executing query"); String results = execResult.dumpToString(); System.out.println(results); Iterator<Node> n_column1 = execResult.columnAs( "n"...

Iterating over a map and putting its values in java

I have created the data structure that is google based guava table and it is shown below final Table<String, String, List<String>> values = HashBasedTable.create(); values.put("ton bon", "currency", Lists.newArrayList("ccdd", "rode1", "cwey", "Certy")); values.put("ton bon", "racy", Lists.newArrayList("wqadd", "werde", "ihtr", "ytre")); Below is the way in which i am iterating over this collection...

count items in a column vaadin

Good day everyone! How do I get the number of items that a column contains? I want to hide the "Workgroup" column if it's empty, I just don't know how. Table tblTeachings = new Table(); tblTeachings.addContainerProperty("#", Integer.class,0); tblTeachings.addContainerProperty("Course",String.class,""); tblTeachings.addContainerProperty("Teaching name",String.class,""); tblTeachings.addContainerProperty("Start date",String.class,""); tblTeachings.addContainerProperty("End Date",String.class,""); tblTeachings.addContainerProperty("Activity...

Exception in thread “main” java.util.InputMismatchException: For input string: “1234567891011”

input:- 1 3 4 7 9 6 -1 output:- 4 6 What I am doing is print the even numbers from the list, one per line. The list ends when -1 is encountered. Below is the my code: Scanner sc=new Scanner(; for (int i = 0; i <100000000; i++) {...

Java dice roll with unexpected random number

I've written a simple Java program to display the results of 20 dice rolls on the console. The results I'm getting are listed below: 3 1 [email protected] 1 5 4 1 [email protected] 1 [email protected] [email protected] 1 6 [email protected] 1 [email protected] [email protected] 1 2 3 3 When I ran it for...

Android Implicit Intent for Viewing a Video File

In my Android app, I have a button that when clicked, launches the external application of my choice to play a video (I gather that this is called an "implicit intent"). Here is the relevant Java code from my onCreate method. Button button = (Button) findViewById(; button.setOnClickListener ( new Button.OnClickListener()...

WebDriver can't get dropdown menu element (Java)

I write a script on Java for Selenium WebDriver, and I have a problem with selected from dropdown menu. Here's my locator: new Select(driver.findElement("FormElement_select_68_input_input"))).selectByVisibleText("Image"); Here's an error: Here's HTML code: Need to select "Image" from this menu, but have an error. Before I had the error like this,...

type conversion if flex

I am using Flerry as Java-Flex bridge for my Flex Desktop Application. How to convert List in Java to ArrayCollection in Flex Flex Code:- [Bindable]public var screenList:ArrayCollection; <flerry:NativeObject id="windowControllerObj" source="ls.window.EnumAllWindowNames" singleton="true" fault="windowControllerObj_faultHandler(event)"> <flerry:NativeMethod id="getWindowNames" name="getAllWindowNames" result="windowControllerObj_resultHandler(event)" fault="getWindowNames_faultHandler(event)"/>...

Numeric literals in Java - octal? [duplicate]

This question already has an answer here: How does a leading zero change a numeric literal in Java? 3 answers Here is some code in java on datatypes: class Test { public static void main(String args[]) { int i = -0777; System.out.println(i); } } The output of the above...

Logging operations in lightadmin

I have a Java web application which use Spring and Hibernate and I plan to use lightadmin to provide an administration interface. However, I found very little information about the logging part of lightadmin : if I have such an adminsitration interface, I would like that any operation made to...

Getting particular view from expandable listview

In my list view I have an textview in expandable group and I want to open the dialog when textview is clicked to fill the information through edittext and update textview. Problem: how could I get the groupview textview item in my fragment oncreateview() method....

Form submit portlet with Spring MVC

I'm trying to achieve a Liferay portlet of submit form using spring MVC. The model: package com.model; public class Person { String firstName; String middleName; public String getFirstName() { return this.firstName; } public String getMiddleName() { return this.middleName; } public void setFirstName(String firstName) { this.firstName=firstName; } public void setMiddleName(String middleName)...

App Not Downloading Newest Version Of File [Java]

Okay, I've been trying to figure this out for a few hours and it's starting to kill me. I wrote a primitive version checker for an app I work on every once and awhile. It's just a simple for fun project. The version checker has been a pain though. It...

SOAP Client, Following an example

I need to consume a SOAP Server named "Mouser" for my company. However I have a problem when I try to send a message. The documentation of my request is : POST /service/searchapi.asmx HTTP/1.1 Host: Content-Type: application/soap+xml; charset=utf-8 Content-Length: length <?xml version="1.0" encoding="utf-8"?> <soap12:Envelope xmlns:xsi="" xmlns:xsd="" xmlns:soap12=""> <soap12:Header> <MouserHeader...

BitmapFont class does not have getBound(String) method

Previously I used getBound method for BitmapFont class in libgdx, but now, I am unable to use it. I cannot find the changes in latest version. Any help is appreciated. Thank you...

Dynamic creation of objects vs storing them as fields

I have this loop which runs about 1,000,000 times. while ((line = br.readLine()) != null) { if(!(line.isEmpty())){ data = new JSONObject(line); name = (String)data.get("name"); surname = (String)data.get("surname"); ar.put(name, surname); //an array } } What are the advantages (if any) in terms of efficiency of having it like that were data,name...

Java Scanner not reading newLine after wrong input in datatype verification while loop

I've looked at similar questions and tried to follow the answers that solved the issues that others have had but putting the or sc.nextLine() after the while loop causes it to go into an infinite loop. The problem is if a user enters incorrect input (nothing or a number)...

Android set clickable text to go one fragment to another fragment

I need to do something like this. Suppose I have 2 fragments A and B.There is a text which can be clickable in fragment A and when user click this text , he can go to fragment B. This example helped me to do it but I think it does...

How can implement long running process in spring hibernate?

as we know the struts interceptor execute and wait will take care of long running process by not getting the request to timeout and destroy it sends wait and at last the desired response i want to implement the same for long running process in spring and hibernate. Thanks....

Unfortunately, (My app) has stopped. Eclipse Android [duplicate]

This question already has an answer here: What is a Null Pointer Exception, and how do I fix it? 12 answers I'm a beginner in android developing and I'm trying to build a simple app but I'm getting this error in the emulator.(Unfortunately,(App) has unexpectedly stopped). LogCat package...

Get network interfaces on remote machine

I know in java we can do NetworkInterface.getNetworkInterfaces() to get all available network interfaces on local machine. Can we do similar thing where I can pass host name to get the NICs(with IPs) which are up and running?

Bulkheading strategies for Akka actors

I have a scenario where an important actor needs to make a call to a slow (15 - 20 seconds) remote system: // Non-actor code equivalent public Result makeSlowNetworkCall(Request request) { Result result = slowServiceClient.soooooSlow(request); // Could be up to 15 - 20 SECONDS (mehhhh) return result; } The Akka...

A beginner questions about printf, java

I'm learning Java by myself and through tutorials online. Just wondering in a printf statement, what does the different %s, %d, %15, %7, %12.2(and so on...) mean? Couldn't find any explanation anywhere online, so I'm turning to you. ...

error: cannot find symbol class AsyncCallWS Android

I'm trying to rewrite the application in this, in Android Studio link, which is written in Eclipse. There are two problems, first problem is there is this line in the project : import com.example.webserviceactivity.R; I couldn't write this one on Android Studio. The second problem is, in this part of...

Can I install 2 or more Android SDK when using Eclipse

I am new to android developments. I am setting up my android development environment using Eclipse. I have a test smart phone with Android version 4.2.2. The automatic installation installed the latest Android SDK version, which is 5.1.1. My questions are: 1. Do I have to install the SDK version...

setOnClickListener error Null object

I saw many questions like mine and I try to fix my codes but failed... this is my code: public class MainActivity extends ActionBarActivity { EditText usernameEditText; EditText passwordEditText; public Button saveme; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); usernameEditText = (EditText) findViewById(; passwordEditText = (EditText) findViewById(; saveme = (Button)...

Join files using Apache Spark / Spark SQL

I am trying to use Apache Spark for comparing two different files based on some common field, and get the values from both files and write it as output file. I am using Spark SQL for joining both files (after storing the RDD as table). Is this the correct approach?...

Get current latitude and longitude android

Requirement: 1.Sometimes(not everytime) I am getting latitude and longitude 0.0. 2.I want to know how to get the location update after user has enabled the gps from the settings. Here is my code public class GPSTracker extends Service implements LocationListener { private final Context mContext; // flag for GPS status...

Interpreting hex dump of java class file

I understand the structure of a java .class file, but when I want to interpret the raw hex data I get a bit lost. This is a hex dump of a class file, excluding the header and constant pool. I understand the header to be the magic number, minor_version and...

@RestController throws HTTP Status 406

I am working on a basic Hello World program using Spring and Restful webservices. But when I try to call my service I am getting below error message: HTTP Status 406 - description - The resource identified by this request is only capable of generating responses with characteristics not acceptable...

Get element starting with letter from List

I have a list and I want to get the position of the string which starts with specific letter. I am trying this code, but it isn't working. List<String> sp = Arrays.asList(splited); int i2 = sp.indexOf("^w.*$"); ...

how to call Java method which returns any List from R Language? [on hold]

How to call java method which returns list from R Language.

How to block writes to standard output in java (System.out.println())

In Java, how to block code from writing to system out? My app calls a 3rd party library that spams logs by issuing numerous System.out.println() calls. I don't have legal rights to decompile and patch the library. I'm running Websphere 8.5.x Considered using System.setOut(PrintStream out), but that will effect the...

Get the min and max value of several items with Comparable

I am trying to get the records with min distance, min speed and max speed in the result of my query. Currently I am getting the shortest distance but I am facing problem to get the min and max speed and I am asking myself whether it is possible to...

why java API prevents us to call add and remove together?

As per Java API- IllegalStateException - if neither next nor previous have been called, or remove or add have been called after the last call to next or previous remove()- Removes from the list the last element that was returned by next() or previous() (optional operation). This call can only...