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Christian Antfeld

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since Oct 31, 2016
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Recent posts by Christian Antfeld

Stephan van Hulst wrote:Why don't you get OpenJDK 15?

All you need to do is unpack the archive somewhere and then set the PATH environment variable to the bin folder.

The real issue is when I try to actually download the JDK from the normal place I have in the past; the Oracle website.  It fails because the download never starts.  Some URLs flash across the bottom of the browser window as if attempting to redirect to another page or connect for a download.  No sign of a download happening is seen.  Nothing in my downloads folder or anything popping up on the bottom of the browser page showing download speed or time etc.

About OpenJDK:  What are the benefits to using this over what's offered from the main Oracle website?  I read through some of the FAQ and like the open standards idea but the point of the whole OpenJDK is lost on me
4 days ago
Has anyone else had issues trying to get JDK 15 SE from the Oracle website?  I've tried on my laptop and desktop and no download starts.  Checked my File Explorer in case I missed it and nothing was there.  Is there something new I need to know before installing?  I know Oracle has been making changes to how Java is licensed and release schedules shorted so maybe I'm missing something.
5 days ago
Thanks Tim.  One last question about this:  I've read a number of comments and maybe an article or two that all mention a similar thing: "knowing technology X, even though it seems to be outdated, is helpful in learning technology Y" given that the two either serve a similar purpose or do essentially the same thing as Ant, Maven, and Gradle all facilitate the development process.

Would I be missing anything by not learning Ant outside of the concept of another tool doing the building and managing of the overall project?  I'm still a little early into understanding the ways Ant, Maven, and Gradle all help with managing larger projects.  To me, they all seem to simplify the process of the overall build of Java and some other languages.  I'm a little lost in the jargon but feel I have the basic picture figured out
2 months ago
I'm getting the feeling I ought to drop the Ant tutorial and go with Maven and/or Gradle.

Is Ant used at all in industry or by anyone for that matter?  It seems to be a dead or nearly dead technology but others say its used when searching online.  
2 months ago
While following the Oracle JDBC tutorial, I made it to the step after changing the build.xml file and corresponding javadb properties and mysql properties files as described in the tutorial.

There were multiple specific errors during compilation and one warning:

Errors: 34 (8 of these) and 36 (two of these)
Warning: regarding a deprecated Object class method called finalize()

Error 34 and 36 both give similar issues mentioning com.sun.rowset not being visible.  Being new to using the jar command, another message directly below the warning says things like "import com.sun.rowset.WebRowSetImpl;".  I'm not sure if this has to do with access levels like public, protected, and private or if visible means something else in the context of the javac tool.  

I could not figure out how to attach an image to show the messages.  Here is one example of the error messages (all of which are nearly identical with different things not being visible):

[javac]   (package com.sun.rowset is declared in module java.sql.rowset, which does not export it)
   [javac] C:\Users\antfe\Downloads\JDBCTutorial\JDBCTutorial\src\com\oracle\tutorial\jdbc\ error: package com.sun.rowset is not visible
   [javac] import com.sun.rowset.WebRowSetImpl;

Link to Oracle JDBC Tutorial (CTRL-F: Compile and Package the Samples to jump to it): Oracle JDBC Tutorial  

2 months ago
When it comes to Java and, I'm assuming, other languages, what are the best practices for developing a plan for getting a project from start to finish?  Currently, I've been writing ideas and flowchart-like English text to draw out the way a program is meant to work.  This isn't done for anyone else to read but to have something to go back and read in the case I don't remember what exactly I was going to do with regard to a particular aspect of a project.  For some reason, writing out what I want a project to look like and how it will be laid out with a "this connects to this for this reason" and going into detail about why and how seemed like a good exercise in clarifying exactly what it is a project does for learning purposes.

I'm asking here because I've gone through so many instances of beginning to learn something about programming be it a language or framework just to find out that it isn't what I should be learning for projects I would want to create.  I would like to avoid that and be able to tell others what is good to do today should I come across the opportunity to avoid my pitfalls.
2 months ago
After moving the unzipped Ant file to Program Files and running the ant -version command, C:\Program Files\apache-ant-1.10.8-bin\apache-ant-1.10.8>ant -version 'ant' is not recognized as an internal or external command, operable program or batch file. is returned. Is something wrong with my installation or am I running the wrong command to check which version I have?

I want to make sure the installation is sound and can be accessed and be used.  I don't want to get deeper into the tutorial and have to turn back all because Ant isn't working correctly.
2 months ago
Thanks, Tim! It seems like I'm starting to get the hang of how things work with setting things up and can stop second guessing myself so much.  My experience here has been so much better than other forums with how much explicit and expedient help I've had.  Love what you're all doing.
2 months ago
I'm going through the process of installing Ant as well and have some confusion about the directory to specify for the env variable value.  The documentation says to use the directory to which Ant was extracted as the variable value.  In my case, it's Downloads.

My first question is: should I have installed it in another location? Perhaps root?  There are only two accounts on my device: Admin and my personal user account (if that has any bearing on what I should do).

2: Should I use C:\Users\username\Downloads\ or drill down further into the directory?  This is more of a Windows path search algorithm question I suppose.  Will the Ant executable be found by ending the variable value at Downloads?

2 months ago
Stephan, thank you.  You clearly understand what I'm asking here.  I wonder why it is that most tutorials and other resources use an IDE right out of the gate but my guess is it makes thjngs simpler for beginners.  I hate doing things that way and really like to know what's going on so I don't get caught out when something weird happens.  I will take your advice and learn the behind-the-scenes stuff like javac and the other tools used in generating a program from source code.

Thank you for explaining the more important things like the resource location requirements.  Its these things that always stop me from moving forward. I know things happen in very specific ways sometimes with computing and I feel i need to know what those requirements are before doing anything at all.

As for the part about the OS dependent CLI, it was probably a wording mistake instead of just saying CLI. I mean terminal or cmd.  I wasn't sure if there were differences between the commands or even the tools in *NIX and Windows and if the IDEs take that into account when running the processes for turning the code into a program.
2 months ago
I've been dabbling in Java for a while now and one thing I find myself being bothered by is not having an overview of how a Java program goes from The highest level of code in the editor to a program that runs on either the local device as a desktop program or a servlet running remotely.  What I do understand is the code is compiled into bytecode then run through the JVM as bytecode.  I know classes are saved in either .java or .class files then converted into whichever of those two it isn't in the initial step.

I'm confused as to how a file open in and IDE goes from code that would run theoretically to a file that runs practically.  I'm familiar with JAR files (an aggregate file of the classes that make up a Java program, correct me if I'm wrong) and that's about it.

I imagine each IDE does things a little bit differently and also believe I read IDEs, among many other programs related or unrelated to creating other programs, all use the OS dependent command line interface to get the work done ostensibly faster than working directly with the CLI manually to compile and call the main method of the program to get it started.  

Other than learning the granular steps taken by IDEs, which sounds like learning how to compile and run programs directly from the CLI, is there a suggested resource to reference to get an overview of how these things work?  Something with the main points of change between what seems to me to be filetypes and properties of those files from source code files to a simple running program on the local machine?

I'm not opposed to learning how this process takes place from the perspective of using the CLI to accomplish these things and the effects each change makes on what is being worked with at each step in the sense of filetype and the composition of those files.  I expect I'll be told to do everything from and IDE to keep things simple and avoid unnecessary pitfalls and learning things not important in today's typical development process and other useless knowledge.  I'm open to any reading and other resources that will help me understand how this takes place.  I feel very frustrated when new terms and concepts come into play along the path to becoming a competent Java programmer and would like to have some high-level knowledge of the process(es) taking place behind the scenes.  

I am a "why?" type of person and hate just doing things because that's how the tutorial says to do it.  I want as much knowledge as possible and this seems to be a good place to start (along with mastering the language's concepts themselves).
2 months ago
What I'm looking for is something similar in presentation to Oracle's class library for the Java language iterations.  I have gone through the Google Maps site to be routed to the GitHub page containing all of the Google Maps resources for their Java API and don't know what to do with those resources to use them in my project.

Is there such a thing as a library for the Java API in a normal readable form to develop some understanding of the use of it or am I going about learning this tool the wrong way?


I've found what I'm looking for and it's such a simple API.  I do have one more question about it being on GitHub and not on Google's website.  Is this a common practice?  I know GitHub is ostensibly the biggest repository but why host their files there?
4 months ago

Junilu Lacar wrote:The name of the .java file must match the name of the class exactly, including capitalization. Your file name starts with a lowercase 'o' whereas the class starts with an uppercase 'O'.

Thanks, that solved it.  Now I'm having issues with the displaying of the components after adding them.  More work to do.
5 months ago

Bob Winter wrote:Please post code and error as text instead of a screenshot. This helps users like me on mobile phones with small screens.

Sorry, Bob. I'll do that from now on.
5 months ago
Without any indication of what I need to fix, I cannot figure out what's going wrong with this program.  What kind of compiler error could this be?

I may try to run this on another computer to see if it's a configuration or Eclipse version issue.

Attachment contains image of program after trying to run it.  Any idea why the red underlined issues exist?
5 months ago