Questions tagged as 'java'

Tagged questions
6
answers

What is the solution to all present, past and future NullPointerException errors?

I have my Java program and I get a NullPointerException and I have seen other questions but they are from people with other programs and it does not work for my program and I want to leave here the 2,000 lines of my program so that you solve the...
asked by 08.01.2017 / 18:54
2
answers

MySQL does not return data to JAVA

I am trying to make a query to my DB but it does not return anything, no error, or some other way of doing it public class test { public static void main(String[] args) throws SQLException { coneccion con = new con...
asked by 15.12.2018 / 22:50
1
answer

How to insert images in JSP?

I have been trying to put a simple image in a JSP project for more than 3 hours, I am just learning how to handle this, and I need to put an image that I have saved in a directory of my pc, I have tried to do it as if programming a html normally...
asked by 16.12.2018 / 04:34
0
answers

Delete and Rebuild BD

I have a database on android, in which by means of a button or something I need the user to delete all the data, all the tables ... Absolutely everything and automatically the tables are generated again could do it? This is my SQLiteOpenHelper c...
asked by 15.12.2018 / 16:30
0
answers

Problem restarting program

I'm creating a game with JFrame, and at the end of each game the user has to choose between continuing to play or exit the program. How can I refresh all the content of the JFrame without having to leave and enter to create a new game? Thanks in...
asked by 15.12.2018 / 18:42
0
answers

Retrieve image saved in a database with mysql in java

Cordial greeting. I need to show me the image in jlabel , the image is already saved in the database, and when I click on the consult button I need you to bring it back and it does not, there is the code that I am trying to implem...
asked by 14.12.2018 / 21:22
0
answers

: Could not find a matching Java operation for WSDD operation "sum"

I have my java class with the webservice        package com.test; import javax.jws.WebMethod; import javax.jws.WebParam; import javax.jws.WebService; @WebService(serviceName = "HolaMundo") public class HolaMundo { @WebMethod(oper...
asked by 17.12.2018 / 18:35
0
answers

How to put a calendar in a Jframe?

In the design part I look for in the palette that offers all the tools to include them in the JF I can not find any calendar.     
asked by 15.12.2018 / 00:02
0
answers

Problems with Packages in JAVA

The problem I'm having with the packages is the following: I need to model a prison system, for which I have to create different classes such as Jail, MaximumSecurity and Minimum Security. These must be found in the package um.prog1.carcel. In t...
asked by 15.12.2018 / 14:32
2
answers

two doubts about arrays in java

I tell you, I have this class on one side static class Item implements Serializable { int Id; String nombre, descripcion; int tipo; //{1-armas, 2-armadura, 3-miscelánea} int experiencia; } //fin clase Item I also have a meth...
asked by 15.12.2018 / 10:32