Develop Reference

Specify JDBI default plugin (SqlObjectPlugin)

Is there a way to tell JDBI I want to use a specific plugin (SqlObjectPlugin in my case) throughout my entire application, without having to re-specify upon each use? Throughout my application code I have the following:
var jdbi = Jdbi.create(dataSource);
jdbi.installPlugin(new SqlObjectPlugin()); // <== I want to make this part DRY
I'm tired of having that second boilerplate line repeated all over my code.
To the JDBI devs: I totally love the product! thx! :)

You have two options, which of the is best depends on the code of your application:
Instantiate Jdbi once and reuse it everywhere (using DI, static singleton, etc)
Use org.jdbi.v3.core.Jdbi#installPlugins, which, according to documentation, uses the ServiceLoader API to detect and install plugins automagically. Some people consider this feature dangerous; some consider it essential -- use at your own risk. But you still would need to call this method every time.

Creating Examples for ScenarioOutline in code

I want to dynamically create multiple examples for a ScenarioOutline in a feature file. Is it possible to do this in the #before hook somehow?
I know this is not how you're supposed to use cucumber, but how would it be possible?
I already tried accesing the Scenario in the hook, but there are no methods to get all steps and their variables/placeholders

This has been asked a couple of times before, usually as the more specific question "How can I import scenario outline examples from CSV?". You might find a workaround that works for you by researching that question, such as this answer that suggests using QAF Gherkin scenario factory, or this answer that suggest passing a CSV into the scenario, and then using the example table to index into it.
BUT, that said, defining scenarios dynamically from file is specifically listed in the Cucumber FAQ as an anti-pattern
We advise you not to use Excel or csv files to define your test cases; using Excel or csv files is considered an anti-pattern.
One of the goals of Cucumber is to have executable specifications. This means your feature files should contain just the right level of information to document the expected behaviour of the system. If your test cases are kept in separate files, how would you be able to read the documentation?
And sometimes when this question gets asked, there's a strong response from people who know the pain of living with a misused BDD tool, practically begging them not to do it.
Cucumber as a BDD tool involves a lot of overhead (writing feature files) and provides a certain value (a vibrant, team-wide understanding of how the product should work, probably). If you write feature files that don't buy you that value, you're investing all this time into an expensive, unnecessary layer of your test framework. Cucumber basically becomes a glorified test runner, and there are much cheaper ways to run your test if you don't really need the value BDD is supposed to provide.

Cucumber doesn't encourage to have examples outside feature file.
However there are few non standard way available with cucumber to use examples outside the feature file. One of them, you can refer in grasshopper's post.
Another alternate is using gherkin with QAF which provides lots of features inbuilt data-providers including XML/CSV/JSON/EXCEL/DB. It also supports to provide example generated through code using custom data-provider. For example:
Scenario Outline: scenario with dynamic test-data
....
Examples:{"dataProvider":"dynamic-examples", "dataProviderClass":"my.project.impl.CustomExamplesProvider"}
package my.project.impl;
public class CustomExamplesProvider{
#DataProvider(name="dynamic-examples")
public static Object[][] dataProviderForBDD(){
//generate and return data.
//This is just example with hard-coded values and you can generate and return data as per need.
Map<Object, Object> ex1 = Maps.newHashMap();
ex1.put("fruit", "grapes");
ex1.put("color", "green");
Map<Object, Object> ex2 = Maps.newHashMap();
ex2.put("fruit", "banana");
ex2.put("color", "yellow");
return new Object[][] {{ex1},{ex2}} ;
}
}

How to run a java file inside of Gatling script?

I am using Gatling for the first time. I have functional tests that are written in java/cucumber. I want to run these functional tests from a Gatling-scala script to do the performance testing of my application. Is there any way to do so?
The idea is to use the existing functional tests and wrap them around gatling scripts so that they could be executed concurrently for multiple users.

What you want to do is to call a Java method from Scala.
Make sure that the method you want to call is available on the class path Scala sees. Then refer to the method you want to call.
This blog post may help you.

If you are using the Gatling for the first time, have you been considering usage of some other performance tools which can provide you such options? As an analog to Gatling for your case (if you want to create functional tests on Java) and run them later using loading tools I would recommend you to check the Locust.
Using Locust you can write the tests using Java or even Kotlin. You can find the handy tutorial by this link:
https://www.blazemeter.com/blog/locust-performance-testing-using-java-and-kotlin
Another preferable option might be to use Taurus framework which allows you to run JUnit/TestNG tests right away:
https://gettaurus.org/docs/JUnit/
https://www.blazemeter.com/blog/navigating-your-first-steps-using-taurus

Gatling is primarily for http testing. what I would do is to call java code from within a gatling test that will return me a value that I check for ex: I return a boolean from a java code below for doing performance test(same also for functional test which needs extending GatlingHttpFunSpec instead of Simulation class). Also will need to use a dummy endpoint (like a health check url which will always return 200).
val myJavaTest: MyJavaTest = new MyJavaTest()
val baseURL="http://localhost:8080"
val endpoint_headers=Map("header1" -> "val1")
val endPoint="/myurl/healthcheck"
setUp(scenario("Scenario ")
.exec(
http("run first test")
.get(endpoint)
.headers(endpoint_headers)
.check(bodyString.transform(str => {
myJavaTest.runTest1()//should return boolean
}).is(true)))
.inject(atOnceUsers(1))).protocols(http
.baseURL(baseURL))

Can Java self-modify via user input?

I'm interested in an executed script allowing user input to modify the process and corresponding source.
What precedents exist to implement such a structure?

Yes, depending on what is meant.
Consider such projects as ObjectWeb ASM (see the the ASM 2.0 tutorial for a general rundown).
Trying to emit the-would-need-to-be-decompiled Java source code is another story: if this was the goal then perhaps the source should be edited, re-compiled, and somehow loaded in/over. (This is possible as well, consider tools like JRebel.)
Happy coding.

You should not be able to modify existing classes. But if you implement a ClassLoader then you can dynamically load classes from non-traditional sources: network, XML file, user input, random number generator, etc.
There are probably other, better ways.

Maybe the Java scripting API is what you're looking for:
http://docs.oracle.com/javase/6/docs/api/javax/script/package-summary.html
http://docs.oracle.com/javase/6/docs/technotes/guides/scripting/programmer_guide/index.html

I wrote an app once that used reflection to allow tests to be driven by a text file. For instance, if you had a class like this:
class Tuner(String Channel) {
tune(){...
play(){...
stop(){...
}
You could execute methods via code like:
tuner=Channel 1
tune tuner
play tuner
stop tuner
It had some more capabilities (You could pass objects into other objects, etc), but mostly I used it to drive tests on a cable box where a full write/build/deploy in order to test took on the order of a half hour.
You could create a few reusable classes and tie them together with this test language to make some very complex and easy to create tests.
THAT is a DSL, not monkeying around with your loose-syntax language by eliminating parenthesis and adding underscores and dots in random locations to make it look like some strange semi-English.

Do you use Java annotations? [duplicate]

This question already has answers here:
Closed 12 years ago.
Possible Duplicates:
How and where are Annotations used in Java?
Java beans, annotations: What do they do? How do they help me?
Over and over, I read about Java 5's annotations being an 'advanced feature' of the language. Until recently, I haven't much used annotations (other than the usual #Override, &c), but work on a number of webservice-related projects has forced my hand. Since I learned Java pre-5, I never really took the time to sit down and grok the annotation system.
My question- do you guys actually use annotations? How helpful are they to you, day-to-day? How many StackOverflow-ers have had to write a custom annotation?

Perhaps the most useful and used case of Java Annotations is to use POJO + Annotation instead of xml configuration files
I use it a lot since (as you already stated) if you use a web framework (like spring or seam) they usually have plenty of annotations to help you.
I have recently wrote some annotations to build a custom statemachine, validations purpose and annotations of annotations (using the metadata aspect of it). And IMO they help a lot making the code cleaner, easier to understand and manage.

Current project (200KLOC), annotations I use all the time are:
#NotNull / #Nullabe
#Override
#Test
#Ignore
#ThreadSafe
#Immutable
But I haven't written yet my own annotation... Yet!

I have used annotations for:
Hibernate, so I don't need to keep those huge XML files;
XML Serialization, so I describe how the object should be rendered in the object itself;
Warning removal for warnings that I don't want to disable (and for which the particular case cannot be properly solved).
I have created annotations for:
Describe the state required in order for my method to be executed (for example, that a user must be logged in);
Mark my method as executable from a specific platform with additional properties for that platform;
And probably some other similar operations.
The annotations that I have created are read with Reflection when I need to get more information about the object I am working with. It works and it works great.

Annotations are just for frameworks and they do work great in hibernate/jpa. until you write a framework that needs some extra information from passed to it objects you wont write your own annotations.
however there is new and cool junit feature that let you write your own annotations in tests - http://blog.mycila.com/2009/11/writing-your-own-junit-extensions-using.html

I use annotations daily and they are wonderful. I use them with jsf and jpa and find them much easier to manage and work with than the alternative XML configurations.

I use annotations for describing in my state synchronisation system what classes are specialisations of the annotated classes, and the environment in which they should be used (when an object is created, it will work out for its entity lists which are the best entity classes to create for the nodes on the network; i.e., a Player entity for a server node is instead a ServerPlayer entity). Additionally, the attributes inside the classes are described and how they should be synchronised across machines.

We just used annotations to create a simple way to validate our POJO's:
#NotEmpty
#Pattern(regex = "I")
private String value;
Then we run this through the Hibernate validator which will do all our validation for us:
import org.hibernate.validator.ClassValidator;
import org.hibernate.validator.InvalidValue;
public void validate(T validateMe) {
ClassValidator<T> validator = new ClassValidator<T>((Class<T>) validateMe.getClass());
InvalidValue[] errors = validator.getInvalidValues(validateMe);
}
Works great. Nice clean code.

We use custom annotations as a part of our integration testing system:
#Artifact: Associates an integration test with an issue ID. Trace matrices are then automatically generated for our testing and regulatory departments.
#Exclude: Ignores an integration test based on the browser platform / version. Keeps the IE 6 bugs from clogging up our nightly test runs :)
#SeleniumSession: Defines test specific selenium settings for each integration test.
They are a very powerful tool, but you gotta use them carefully. Just have a look at those early .NET Enterprise class files to see what a nightmare mandatory annotations can be :)

We have a report builder as part of our webapp. A user can add a large number of widgets that are all small variations on the same set of themes (graphs, tables, etc).
The UI builds itself based on custom annotations in the widget classes. (e.g. an annotation might contain default value and valid values that would render as a dropdown. Or a flag indicating if the field is mandatory).
It has turned out be be a good way to allow devs to crank out widgets without having to touch the UI.