I have several VB programs that I wrote a few years ago in school. Is there any way possible to convert those programs to Java? Or would that it be easier to just rewrite it from scratch? My goal is to create an Android app that combines at least two of the programs into one functional app. This is purely a nonprofit endeavor; I'm a full time firefighter and am looking to put a free tool in the hands of my guys and other firemen who might want to use it.
I've been unable to locate the source code for the programs and have searched for an answer but haven't been able to find a definitive answer as most answers cover the source, not the compiled result. I've downloaded a couple supposed VB decompilers to see the results, but, in order to see the 'full' results, all the ones I've used require purchasing a 'pro' version. I have no problem paying for such a version, but I'd like to know if it's going to work properly before I do.
It would definitely be faster to rewrite them than it would be to devise a way of converting a VB program into Java code. Not only are the languages quite dissimilar, but VB's UI model is nothing like Android's, so it would likely be impossible (or at least impractical) to translate the UI code automatically.
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I have been working on a project alone for more than two years for a company. The project is a really big one using rxtx to communicate with a hardware device. I used Java 8 and JAVAFX for the UI. Now it is almost finished and I am starting to search how to deliver the end user application that the company will distribute over its clients.
The problem is that the company I am working with wants the code to be non reachable when the software is between final clients hands because the Java code contains some extremely sensitive information that could have very bad consequences for the company if final clients happened to know them. The clients can literally perform actions they don’t have the right to perform.
So after searching (a lot) and thinking relatively to my case, I understood that giving a JAR obfuscated isn’t the solution. I then tried to generate a JAR and then transform it to an EXE but all I succeeded on was wrapping the JAR into EXE which does not prevent extracting the JAR and then seeing all the code easily. Finally, I found that I should use AoT compilation like GCJ compiler to produce native binary exe from my Java code but here I am stuck because after watching videos and reading articles etc I didn’t manage to find a clear way to produce the native binary exe.
I am now confused since I don’t know if I am on the right path and good direction or if I am totally wrong and there is another way of protecting the code (at least from non professional hackers, I understand that it is not possible to make it 100% safe but I am just searching for a reasonable and good way). How should I manage this final step of my work?
I currently work for a company that has code that we don't want anyone to have access to for the security of our clients and-- less important-- for legal reasons. ;-)
One possible solution you could look into would be to rewrite the code you deem most sensitive into a C/C++ library. It would be possible to compile this into a .so/.dll/.dylib file for the respective OSs and it would make it difficult, not entirely impossible, but difficult to decompile.
The trouble would come from learning how to access native code from Java as much of the documentation is not helpful or just simply nonexistent. This would utilize the Java Native Interface (JNI) which allows Java to, well, interface with the native (compiled C/C++) code. This would make it possible to create a Jar file that would effectively become a Java library for you to access throughout the rest of your project. The native code, however will still need to be loaded at runtime, but that's apart of learning how JNI works. A helpful link I found for JNI is http://jnicookbook.owsiak.org/ (for as long as it's still a functional link).
One of our clients here where I work has a project written in Java and needed to implement our code that is unfortunately all written in C. So we needed a way to access this C/C++ code from Java. This is the way we went about solving this issue without rewriting our code in Java. But we had the benefit (?) of having already written our code in C.
This solution to write a bunch of extra code last minute in another language that I may or may not be familiar with doesn't sound like particularly fun time.
I would be curious to learn what possible problems others might see with this solution.
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Getting a clue at / debug a huge Java Swing App I’ve inherited
I joined a new project and have to understand the project's product. I am more familiar with daemon/standalone type applications but this time i have to get involved in Java GUI applications using Swing.
I have to familiarise myself with quite a large code base. I have been trying to do this for the last 3 days and find that i am struggling to get the "Big picture". The event driven model means that things can happen and are triggered from anywhere within the application.
At the moment i am still struggling to work out how the screen is built and put together. I can see the code but just struggling to follow because it is not the usual model that i am used to where you can just follow the references, calls etc.
Is there anything i can do to simplify/speed this learning process? I tend to understand things better when i see them in a diagrammatic form (class diagrams, sequence diagrams etc.). I am trying to see if i can try and find a tool that can reverse engineer the code to UML so that i can get a better understanding but because the code base is huge, the UML diagrams that will be generated will probably be unusable because of the number of classes involved.
Any advice would be appreciated.
Guess you are dealing with a legacy application and all the bagage that comes along with it.
So even if you got to generate a UML, I am willing to bet that it will not help you, since you will (most likely) find it to be a giant mess. Things that used to resemble a Design Pattern got messed up, code snippets copied and pasted from a to b to c, etc...
Your best bet (from my experience) is to follow the Programm logic in the debugger when you execute certain actions. At least thats what I found to be most useful when faced with similar senarios.
Get good IDE. I would recommend itellij idea for this task. It's not free, but it beats eclipse on every occasion
I agree with dngfng, a legacy application will come with its 'baggage'. Only 'time' and lot of discussion with existing developers will sort that.
Along with the other suggestions here, I d say just 'use' the product from the user point of view. Perform all the actions that are promised in the features till you get a hang of using the software. After that when you look at the codebase, it may get a little more intuitive.
I am going to create a Text to speech converter, which can be executed in both Windows, and Linux based systems. Can someone please help me answer the following questions;
What language should i use; Java, C++ or any other?
The program i am going to create should be able to read large chunks of data.
There should be good sound quality.
What are the libraries available to achieve this?
Please share your experiences as well.
Use the language you're most comfortable with. I learned the hard way when I tried to re-code my raytracer in C++, coming from a Python background. It took me weeks to get it to function...
Basically, you'll get frustrated by the nuances of a new language before you can get to coding something, so I suggest you stick with what you know.
That's independent of the language. Just makes sure to read the data in chunks (like 2048 kilobytes at a time). Reading a big file to RAM is not a great idea, as you can't be sure your end user has enough RAM (audio files can get BIG).
This is trivial. I can't help you program good sound quality. That's up to you.
There exist a few implementations of TTS for Linux, so that's all I can recommend. Look at Festival, as it is one of the ones you can actually understand.
Long time ago i had that same idea. I think it is not too complicated and can be done. This is how i would do it:
1- I would use Java, because it is platform independent.
2- If you are going to create an standalone application, it will be the local computer that will do the processing an not an application server, as in the case of web apps. Also i suppose that your program, will be used only by one user at a time. I think you will not have big issues with the amount data to process, if u implement some buffering mechanism.
3- The quality of the sound will depend in various factors such as: noise when recording,format, speed of the sound... Notice that many text to speech applications that exist on the web, the sound quality is ok, but you will never get the feeling that it is a real person, who is reading. (I recommend you a female voice, it sounds better).
4- Regarding to the libraries and another gadgets, this is what i think you might need:
-Java Standard Development Kit(To be able to work with java)
-A good IDE: There a many out there you can get for free. My favourite is eclipse but if you are a beginer with java, you might like to start with netbeans many people say it is more intuitive for learning.
-JLayer Mp3 library This will help you play the sounds in java.
-javax.swing Is a java library that is included in the development kit and allows you to create rich graphical user interfaces. Also if you are new to swing, i would recommend you a great swing IDE, called JFormDesigner, have a look at it, im sure it will speed your development alot(It is a great tool).
I hope my answers can give you some tips.
Update
I think it would be correct to mention also, that the only minimum requirement the users of your app will have in order to run the app is:
JRE(Java runtime enviroment)
This project of text to speech can be made using computer generated voice
so no problem of storing a database for each word and its pronunciation.
Just use the language in which u feel master to urself and apply the concept.....
I do not know anything about text to speech except that it's not easy. That being said, I suggest you stick with the language you are most familiar with. I'm sure Java and C can do it.
I have a database I have created in Delphi that’s still in the testing phase
I found it easy to give access to my database through Java in the form of a *.dll
but this is not just a standard database (its very cutting edge with Nodes).
It’s taken me a lot of learning to get to this point. I very much appreciate the help and thanks of this forum and the replies I have received to my questions to get me hear.
What it very exciting at the moment is Android devices and to write in java
But I know nearly nothing about Java. The developers are like five times more busy than Delphi. The Google apps web page is averaging about 40 hits a day and thats only a part of java.
I want to make it accessible to the Maven approach to using databases that I have no documentation on how to do this yet.
I know I have ShortIntegers, LongIntegers, I'm not sure about strings that originate as ANSCI but can be UTRF-8 and other things. Do I have double numbers and do I have date records.
Do I have any other type data types in java
Can any one enlighten me please.
Java for dummies
If you are Delphi programmer then you you know how to program: you know loops, routines, variables, objects etc. Java differs from Delphi in many things, but it is hard to say what will make problems to you. You must give it a try.
Install JDK
Read some good Java book. You can find some good free books such as older edition of Thinking in Java
Fire good text editor. You can start with Eclipse or Netbeans, but there are many simple editors with Java syntax highlighting that may be better for Java novice
Start writing programs in Java.
First, I have no experience doing this. But like the beginning of any good program, I have problem that I need to fix, so I'm willing to learn.
So many of you are probably already familiar with pdftk, the handy utility for handling various pdf-related tasks. So far as I can tell, most of these features are available in much newer, lighter libraries/extensions, except the one I need (and probably the only reason it still exists): merging form data files (fdf and xfdf) with a form PDF and getting a new file as the output.
The problem is that my server doesn't have gcj, which is fundamental to build/compile pdftk. I don't know if it's because I'm on Solaris or if it's for some other sysadmin-level reason, but I'm not getting gcj anytime soon. And there are no pre-compiled binaries for Solaris as far as I can find.
So I'm thinking that the MAKE file and C code can be rewritten to import the Java library (very ancient version of itext) directly, via javac.
But I'm not sure where to really start. All I know is:
I want a binary when I'm done, so that there won't be a need for a Java VM on every use.
The current app uses GCJ.
So my first thought was "Oh this is easy, I can probably just call the classes with some other C-based method", but instead of finding a simple method for doing this, I'm finding tons of lengthy posts on the various angles that this can be approached, etc.
Then I found a page on Sun's site on how to call other languages (like C) in a Java class. But the problems with that approach are:
I'd have to write a wrapper for the wrapper
I'd probably be better off skipping that part and writing the whole thing in Java
I ain't ready for that just yet if I can just import the classes with what is already there
I'm not clear on if I can compile and get a binary at the end or if I'm trapped in Java being needed every time.
Again, I apologize for my ignorance. I just need some advice and examples of how one would replace GCJ dependent C code with something that works directly with Java.
And of course if I'm asking one of those "if we could do that, we'd be rich already" type questions, let me know.
I'm not sure what you are looking for exactly, so I provided several answers.
If you have java code that needs to run, you must:
Run it in a jvm. You can start that vm within your own custom c-code, but it is still using a jvm
Rewrite it in another language.
Compile with an ahead-of-time compiler (eg gcj)
Incidentally, you could compile a copy of gcj in your home folder and use that. I believe the magic switch is --enable-languages=java,c (see: here for more)
If you have c-code you want to call from java, you have four options:
Java Native Interface (JNI). It seems you found this
Java Native Access (JNA). This is slower than JNI, but requires less coding and no wrapper c-code. It does require a jar and a library
Create a CLI utility and use Runtime.Exec(...) to call it.
Use some sort of Inter Process Communication to have the Java code ask the c-code to perform the operation and return the result.
Additional platform dependent options
Use JACOB (win32 only: com access)
I am not sure if I understand what you are looking for.
If you are looking to incorporate the C code into Java to make a native binary without the gcj, I think you are out of luck. You can include the C in Java, but it would be a primarily Java program meaning you would need the JVM on each run. Is there anything stopping you from compiling the gcj yourself?