Questions tagged as 'java'

Tagged questions
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Error mixing versions in the Gradle App with Firebase libraries

I'm trying to synchronize the libraries 'com.google.firebase:firebase-core:16.0.4' and 'com.google.firebase:firebase-database:16.0.4' in the Gradle but I skip the error of those libraries do not correspond to the others....
asked by 31.10.2018 / 09:47
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Access an attribute of a HashMap for a .ftl view with Java

I'm trying to access an attribute of a Java object but I can not get it. I have the controller where I create the object and add the data: Email emailModel = new Email(); buildMailModel(emailModel); Map<String, Object&g...
asked by 31.10.2018 / 13:32
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Update the value of a column of a BBDD

My problem is that I have to update the TOTAL_IMPORT field in the Customers table with the sum of the delivery notes (that match the client code, from the Customers table, that the user puts in) that are found in the Lines table. The client code...
asked by 31.10.2018 / 12:34
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reset a jcombobox at the end of completing the form

I'm filling out a form. To avoid the error of the user in one of the campos to fill it I limit it to a combobox , and when it completes the filling and sends, I can delete everything, but the combobox remains in the value...
asked by 31.10.2018 / 11:00
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constraintviolationexception Duplicate field

The error is that when I create a user with the same alias I get the exception constraintviolationexception. I tried to perform a try catch on the controller method but it does not catch me and it continues to skip the exception User Class...
asked by 20.11.2018 / 09:41
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Implement websocket that requires headers in java

I am making an application to collect a series of data from several websites. In one of them to do so I must communicate with the server through a WebSocket. This WebSocket has a series of parameters in the Header: Connection: Upgrade...
asked by 20.11.2018 / 09:53
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configure JProgressBar when assigning the .xls to WorkbookFactory poi java

I am using the Apache POI library in a JAVA project to work with Excel files and I need to show the load percentage in a JProgressBar when this line is executed: libro = WorkbookFactory.create(new FileInputStream(ruta)); Note: I already kno...
asked by 31.10.2018 / 22:13
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alarmManager does not work on android 8

I have an app that needs to be launching notifications 2 times a day in a specific time, as if it were a reminder. Currently this functionality I'm doing with alarmManager, the problem arises with phones with android 8 since this does not allow...
asked by 31.10.2018 / 19:11
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How to read csv file in servlet?

This is trying to read a csv file in a Servlet / java, the problem is when reading the file in particular and know your data. This is the form where I sent the file to the Servlet. <form id="form" method="post" class="upload-box" action...
asked by 30.10.2018 / 18:49
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Builders in java

Hello friends, sorry, I am studying java and in the classes the teacher touched on the topic of "java builders" and I did not really understand it. Well what I understood is this:    A constructor is similar to a method but only serves to...
asked by 06.10.2016 / 01:31