Questions tagged [jakarta-ee]
Jakarta EE (formerly known as Java Enterprise Edition, Java EE, and J2EE) is a specification defining a collection of Java-based server and client technologies and how they interoperate. Use this tag for questions about Jakarta EE runtime/platform in general. For the more specific API questions, please use more specific tags such as [servlets], [jpa], [cdi], [jaxb], [jsf], [jsp], [jms], [ejb], etc.
jakarta-ee
29,351
questions
887
votes
16
answers
458k
views
What is the difference between JSF, Servlet and JSP?
I have some questions. These are :
How are JSP and Servlet related to each other?
Is JSP some kind of Servlet?
How are JSP and JSF related to each other?
Is JSF some kind of Pre-Build UI based JSP ...
- 15.5k
678
votes
22
answers
596k
views
What's the difference between JPA and Hibernate? [closed]
I understand that JPA 2 is a specification and Hibernate is a tool for ORM. Also, I understand that Hibernate has more features than JPA 2. But from a practical point of view, what really is the ...
- 35.3k
618
votes
9
answers
385k
views
428
votes
5
answers
372k
views
Why use @PostConstruct?
In a managed bean, @PostConstruct is called after the regular Java object constructor.
Why would I use @PostConstruct to initialize by bean, instead of the regular constructor itself?
- 9,597
395
votes
12
answers
224k
views
What is Java Servlet?
I read many articles to understand Java servlet but I did not succeed.
Can you please give brief introduction of Java servlets (in easy language). What is a servlet? What are the advantages?
I can't ...
- 9,261
385
votes
8
answers
457k
views
Why does JPA have a @Transient annotation?
Java has the transient keyword. Why does JPA have @Transient instead of simply using the already existing java keyword?
- 91.3k
367
votes
1
answer
620k
views
Java 11 package javax.xml.bind does not exist [duplicate]
I'm trying to deserialize XML data into a Java content tree using JAXB, validating the XML data as it is unmarshalled:
try {
JAXBContext context = JAXBContext.newInstance("com.acme.foo");
...
- 24k
325
votes
14
answers
430k
views
Difference between Java SE/EE/ME?
Which one should I install when I want to start learning Java? I'm going to start with some basics, so I will write simple programs that create files, directories, edit XML files and so on, nothing ...
- 82.8k
299
votes
11
answers
163k
views
Replacements for deprecated JPMS modules with Java EE APIs
Java 9 deprecated six modules that contain Java EE APIs and they are going to be removed soon:
java.activation with javax.activation package
java.corba with javax.activity, javax.rmi, javax.rmi.CORBA,...
- 50.1k
264
votes
12
answers
109k
views
Eclipse add Tomcat 7 blank server name
I was trying to add Tomcat 7 in my Eclipse in Ubuntu. When I click "Add new server" in Eclipse and select "Tomcat v7.0 Server", the field "Server Name" is blank and I cannot type in anything in that ...
- 11.9k
237
votes
11
answers
304k
views
Maven dependency for Servlet 3.0 API?
How can I tell Maven 2 to load the Servlet 3.0 API?
I tried:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version&...
- 91.3k
235
votes
9
answers
177k
views
What is Java EE? [duplicate]
I realize that literally it translates to Java Enterprise Edition. But what I'm asking is what does this really mean? When a company requires Java EE experience, what are they really asking for? ...
- 28.6k
230
votes
6
answers
276k
views
Where to place and how to read configuration resource files in servlet based application?
In my web application I have to send email to set of predefined users like [email protected], so I wish to add that to a .properties file and access it when required. Is this a correct procedure, if ...
- 4,259
223
votes
9
answers
64k
views
Java / Jakarta EE web development, where do I start and what skills do I need? [closed]
I want to learn, at least at a basic level, how to build Java web applications (coming from a .NET background). I would like to be able to build, deploy a simple CMS type application from the ground ...
- 102k
220
votes
7
answers
242k
views
Can someone explain mappedBy in JPA and Hibernate?
I am new to hibernate and need to use one-to-many and many-to-one relations. It is a bi-directional relationship in my objects, so that I can traverse from either direction. mappedBy is the ...
- 20.2k
213
votes
20
answers
216k
views
Intellij IDEA Java classes not auto compiling on save
Yesterday I switched to IntelliJ IDEA from Eclipse.
I am using JRebel with WebSphere Server 7 as well.
Everything now seems to be working somewhat fine, except that when I modify a Java file, and ...
- 22k
210
votes
15
answers
331k
views
How to change context root of a dynamic web project in Eclipse?
I developed a dynamic web project in Eclipse.
I can access the app through my browser using the following URL:
http://localhost:8080/MyDynamicWebApp
I want to change the access URL to:
http://...
- 34.4k
207
votes
8
answers
230k
views
Please explain about insertable=false and updatable=false in reference to the JPA @Column annotation
If a field is annotated insertable=false, updatable=false, doesn't it mean that you cannot insert value nor change the existing value? Why would you want to do that?
@Entity
public class Person {
...
- 38.6k
202
votes
31
answers
887k
views
Could not calculate build plan: Plugin org.apache.maven.plugins:maven-resources-plugin:2.5 or one of its dependencies could not be resolved
org.apache.maven.plugin.PluginResolutionException: Plugin org.apache.maven.plugins:maven-resources-plugin:2.5 or one of its dependencies could not be resolved: Failed to read artifact descriptor for ...
- 3,014
201
votes
9
answers
276k
views
What is the difference between Spring, Struts, Hibernate, JavaServer Faces, Tapestry?
May I know what is the difference between:-
Spring
Struts
Struts 2
Hibernate
JavaServer Faces
JavaServer Pages
Tapestry
Are these technologies/framework complementary to each other? Or they are ...
- 2,367
196
votes
7
answers
69k
views
What exactly is Java EE?
I have been doing Java SE for some years now and moving on to Java EE. However, I have some trouble understanding some aspects of Java EE.
Is Java EE just a specification? What I mean is: Is EJB Java ...
- 1,979
192
votes
4
answers
91k
views
EJB's - when to use Remote and/or local interfaces?
I'm very new to Java EE and I'm trying to understand the concept of Local interfaces and Remote interfaces. I've been told that one of the big advantages of Java EE is that it is easy to scale (which ...
- 9,417
191
votes
4
answers
120k
views
How to define servlet filter order of execution using annotations in WAR
If we define webapp specific servlet filters in WAR's own web.xml, then the order of execution of the filters will be the same as the order in which they are defined in the web.xml.
But, if we define ...
- 16.3k
181
votes
15
answers
321k
views
Deploying Maven project throws java.util.zip.ZipException: invalid LOC header (bad signature)
I am getting the below exception when I run my mvn install. I have even deleted the local repository and ran again getting same exception.
[ERROR] Failed to execute goal
org.apache.maven.plugins:...
- 1,963
180
votes
11
answers
287k
views
What does the servlet <load-on-startup> value signify
I am getting a bit confused here. In our application we are having a few servlets defined. Here is the excerpt from the web.xml for one of the servlets:
<servlet>
<servlet-name>...
- 8,379
168
votes
9
answers
123k
views
Should I use @EJB or @Inject
I have found this question: What is the difference between @Inject and @EJB but I did not get any wiser. I have not done Java EE before nor do I have experience with dependency injection so I do not ...
- 48.7k
167
votes
11
answers
353k
views
Another Repeated column in mapping for entity error
Despite all of the others post, I can't find a solution for this error with GlassFish, on MacOSX, NetBeans 7.2.
Here the error :
SEVERE: Exception while invoking class org.glassfish.persistence.jpa....
- 3,243
164
votes
5
answers
96k
views
What is an EJB, and what does it do?
Been trying to learn what EJB beans are, what does it mean their instances are managed in a pool, blah blah. Really can't get a good grip of them.
Can you explain me what they really are (practically ...
- 7,314
160
votes
4
answers
151k
views
Performing user authentication in Java EE / JSF using j_security_check
I'm wondering what the current approach is regarding user authentication for a web application making use of JSF 2.0 (and if any components do exist) and Java EE 6 core mechanisms (login/check ...
- 7,833
154
votes
22
answers
288k
views
web.xml is missing and <failOnMissingWebXml> is set to true
Consider:
When I create a simple Maven project in Eclipse I am getting this error:
web.xml is missing and <failOnMissingWebXml> is set to
true
How can I fix this problem?
- 1,706
153
votes
1
answer
7k
views
How can a JACC provider use the Principal-to-role mapping facilities of the server it's deployed on?
I am writing a JACC provider.
Along the way, this means implementing a PolicyConfiguration.
The PolicyConfiguration is responsible for accepting configuration information from the application server,...
- 15.9k
152
votes
14
answers
183k
views
Servlet for serving static content
I deploy a webapp on two different containers (Tomcat and Jetty), but their default servlets for serving the static content have a different way of handling the URL structure I want to use (details).
...
- 46.8k
148
votes
10
answers
84k
views
Describe the architecture you use for Java web applications? [closed]
Let's share Java based web application architectures!
There are lots of different architectures for web applications which are to be implemented using Java. The answers to this question may serve as ...
141
votes
11
answers
169k
views
Simplest way to serve static data from outside the application server in a Java web application
I have a Java web application running on Tomcat. I want to load static images that will be shown both on the Web UI and in PDF files generated by the application. Also new images will be added and ...
- 3,707
138
votes
35
answers
201k
views
Questions every good Java/Java EE Developer should be able to answer? [closed]
I was going through Questions every good .Net developer should be able to answer and was highly impressed with the content and approach of this question, and so in the same spirit, I am asking this ...
138
votes
11
answers
177k
views
What's the main difference between Java SE and Java EE? [duplicate]
What's the main difference between Java SE and Java EE?
- 139k
137
votes
2
answers
59k
views
Where to use EJB 3.1 and CDI?
I am making a Java EE based product in which I'm using GlassFish 3 and EJB 3.1.
My application has session beans, a scheduler and uses web services. I recently came to know about Apache TomEE, which ...
- 2,156
137
votes
4
answers
235k
views
How to create and handle composite primary key in JPA
I want to have versions from the same data entry. In other words, I want to duplicate the entry with another version number.
id - Version will be the primary key.
How should the entity look like? ...
- 6,664
136
votes
9
answers
63k
views
Would you, at present date, use JBoss or Glassfish (or another) as Java EE server for a new project? [closed]
If you started a new Java EE project today which is to be finished in about a year, which application server would you choose and why?
Part of your answer should include your arguments for your ...
133
votes
10
answers
335k
views
How to generate JAXB classes from XSD?
I'm a total newbie with XML. I'm doing a Java EE project REST implementation and we return a lot of XML. With this we decided to use JAXB. So far, we manually coded the Models for the XML.
But there ...
- 5,294
132
votes
5
answers
69k
views
What is the difference between an application server and a servlet container?
I am trying to understand the difference between a full fledged application server (e.g. Weblogic, JBoss etc.) and a servlet container (Tomcat, Jetty etc.).
How do they differ and when to use which?
- 7,540
126
votes
9
answers
58k
views
Why is spawning threads in Java EE container discouraged?
One of the first things I've learned about Java EE development is that I shouldn't spawn my own threads inside a Java EE container. But when I come to think about it, I don't know the reason.
Can you ...
- 18.7k
125
votes
2
answers
24k
views
Difference between JSP EL, JSF EL and Unified EL [closed]
I would like to know the detailed difference between the Expression Languages (EL).
There is JSP EL, JSF EL and Unified EL.
I would like to know the history behind the EL and what the latest EL is ...
- 7,234
122
votes
1
answer
142k
views
What is the difference between Eclipse for Java (EE) Developers and Eclipse Classic?
What is the difference between Eclipse for Java (EE) Developers and Eclipse Classic?
Both are marked as version 3.6.
Which one should I use?
- 41.1k
121
votes
5
answers
182k
views
When to use EntityManager.find() vs EntityManager.getReference() with JPA
I have come across a situation (which I think is weird but is possibly quite normal) where I use the EntityManager.getReference(LObj.getClass(), LObj.getId()) to get a database entity and then pass ...
- 1,767
116
votes
5
answers
82k
views
Backing beans (@ManagedBean) or CDI Beans (@Named)?
I've just started reading through Core JavaServer Faces, 3rd Ed. and they say this (emphasis mine):
It is a historical accident that there are two separate mechanisms, CDI beans
and JSF managed ...
- 358k
116
votes
31
answers
159k
views
How to improve Netbeans performance?
Is there a real way to get Netbeans to load and work faster?
It is too slow and gets worse when you have been coding for some time. It eats all my RAM.
I am on a Windows machine, specifically ...
- 5,307
114
votes
3
answers
104k
views
Problems with making a query when using Enum in entity
I have the following in a Question entity:
@NamedQuery(name = "Question.allApproved",
query = "SELECT q FROM Question q WHERE q.status = 'APPROVED'")
and
@Enumerated(EnumType.STRING)
private ...
- 48.7k
113
votes
6
answers
102k
views
JPA map collection of Enums
Is there a way in JPA to map a collection of Enums within the Entity class? Or the only solution is to wrap Enum with another domain class and use it to map the collection?
@Entity
public class ...
- 5,706
112
votes
8
answers
119k
views
What is the difference between web server, web container and application server? [duplicate]
What is the difference between web server, web container and application server?
- 3,376