Questions tagged as 'java'

Tagged questions
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Tomcat v8.5 does not boot, displays error: Child container failed during start

I'm doing a college work, a simple crud with JSF2, Hibernate, Primefaces and CDI. But at the moment I'm going to start the project in Tomcat I get the following error: GRAVE: A child container failed during start java.util.concurrent.Execution...
asked by 27.08.2017 / 19:01
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ForEach returning only one object in the list

I have a JSP page and I want it to be a list. To do this, I created a listarTodos() method inside the DAO class and set the fields to show the data of the object, thus getting the code: </div> <% ProdutoD...
asked by 06.09.2017 / 00:56
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Error "ConcurrentModificationException" when modifying (insert data in) ArrayList

I'm trying to create a small login system in Java. I have the following classes: LoginController: public static void main(String[] args) { ArrayList<Usuario> listaUsuarios = UsuarioController.listaUsuarios; // Adiciona um...
asked by 06.09.2017 / 01:43
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I can not get return value of the onSuccess method (Uri uri) [closed]

For my college CBT I'm developing an android app. I stopped at a point where I'm downloading the URL of some Firebase Storage images, and within the onSuccess(Uri uri) method, I have access to the uri variable where the URL of the...
asked by 06.09.2017 / 03:00
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Error initializing application with Spring Boot

I'm creating an application using Spring Boot with JPA. When I upload the application, the following message is displayed:    Description:   Can not determine embedded database driver class for database type NONE   Action:   If you want an em...
asked by 08.09.2017 / 02:33
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Read PDF or TXT file in java

Hello. I'm doing a course work where I have to get a PDF file or the TXT that the teacher passed, and encrypt it by Cesar's cipher algorithms, playfrai and transposition. I would like to know how I do for my algorithm to read this file or in PDF...
asked by 08.09.2017 / 05:22
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How do I know if a file exists in Storage Firabase?

I am using Firebase Storage to store user profile photo, I made a method to fetch the image and put it in an ImageView. It works great when the image exists in Firebase, but when it does not exist, it leaves ImageView with nothing, neither the s...
asked by 29.08.2017 / 02:05
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Advantage and disadvantage between onClick and setOnClickListener

I have a certain situation where we see that it is possible to create in the XML file a property called onClick : onClick: XML: <Button android:layout_height="@dimen/edittext_min_height" android:layout_alignParentLeft="true" and...
asked by 26.10.2016 / 14:09
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Set CLASSPATH to be accessible in Apache

How can I make the environment variable CLASSPATH accessible by apache? I have a Django project that uses the python-weka-wrapper library that bridges Weka's Java implementation. Everything works perfectly on the Django devel...
asked by 08.09.2017 / 18:37
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Help with Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string:

I'm finalizing a code in java but I came across the above error and I can not solve it. When I mark the checkbox the fields are formatted, when I uncheck I get the exception above. Can anyone tell me where I'm going wrong: I'll leave the clas...
asked by 10.09.2017 / 01:39