Can you extract source from tomcat application? The webapp is not deployed as a .war file, it's a bunch of directories, xmls, configurations, .class files, .jars and stuff.
Your comments to Paul Tomblin indicate you already have access to the server. As he said, if you didn't upload the source to start with (which is normal), you can't get it off the server. However, there are a couple of things to note:
Unless you compiled your JSPs prior to uploading, they will contain their own source code and you can download them for use in another project or whatever it is you're trying to do
If you're desperate, you can decompile the .class files using something like JD (http://java.decompiler.free.fr). The decompiled code will not include comments and is not always spot-on, but it will get you much further than you are now.
You don't have to put the source code on your web server, just the compiled class files. So no, if the source isn't on the server, nobody can "pick it up". In a normal configuration, I don't think it's possible even to download the individual class files, but it might be possible if you put your Tomcat webapps directory somewhere where your normal web server (Apache) can find them.
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I'm kinda new to spring and web development as a whole.
My question is:
When you build a spring boot project (using Maven) into jar file and deploy it via Docker, everything is in one jar file. How can you access your resources (css, js, images, html...) if you want to edit something? Like change something in css file or add something to html page. Is it even possible? Or do you have to build a new jar file everytime, when you need to change something (in frontend)? Also, when there are being uploaded some images or other files, where are they stored? This stuff is very confusing for me and i can't find any related books or help at all.
Thanks for help!
when you package any java program it is nothing but a zip file. Based on what kind of package it is, you wither name it as a Jar or War.
Jar == Java archive
War == Web archive
Now, given the fact that jar and war both are essentially a zip archive, it gives you flexibility to extract and modify them just like any other zip file.
On windows, I think softwares like 7zip let you update the jar inline. I have done it multiple times, especially when I wanted to change application.properties alone on cloud machines, and no other code changes were required. In such cases, building the whole jar and transferring it again to cloud machine could be time consuming. So I would just extract the contents, update whatever I want to, and rezip the package.
Here is the commands you can use -
jar xf jar-file
This should extract the files into a directory.
This SO thread will guide you towards creating jar files.
Something like jar cf myJar.jar ** should be enough to generate a jar file IMO, but syntax might vary.
The jar file is actually just a zip file containing all the files and classes of your application, so technically you can change files in it like any other zip archive. Best practice is to build the jar file using Maven or Gradle from source every time you need something changed.
It's good practice to keep the source in version control using Git, and tag each build in the git repository - that way you can easily keep track of changes to the jar file by looking at what's in git at the time of the build.
I do not have the latest source code but have the war(up to date) file deployed on server.
Please suggest the best ways to
1) Retrieve source code from war/ear
2) Compare & Merge/update the available source code with the code present in war/ear but missing in available source code(I am using ECLIPSE IDE)
Thanks in advance
War files are basically zip files, so they are easy to extract. (using unzip or just renaming the file)
Next you could use a Java decompiler like JD.
But you won't get the original Java code as the compiler does a lot of optimization.
But it should give you a good starting point
Once you've extracted the classes from the EAR/WAR/Jars, use JAD to decompile the code you're interested in to get back to the source: http://varaneckas.com/jad/
I'm not sure there's any out-of-the-box tool that is going to compare/diff your original source with the decompiled source produced from something like JAD though. Also bear in mind, decompiling classes back to source is not going to produce source that looks identical to the original source - code style is going to be different, maybe even some structure of the code. It's going to be difficult to do a diff between the original source and decompiled source.
If you have the original source but not the source for the code that is currently deployed, maybe a better question is to ask 'why not'? If there's something missing in your build process where you are not tracking what source is being used for each build, maybe this is an easier issue to address moving forward, rather than trying to do something clumsy and error prone like a diff between some other source and decompiled source?
The exact answer: it is not possible to get the original source code (.java files) from a war as opposed to a jar (java archive). When you create a jar file, you can decide if you want to include the .java files. Only a java decompiler can help, see the other answers.
Using JD GUI you can the source code with java code, but you'll need to
Inside the war folder, under specific module - Based on your project hierarchy (if maven project -these config will be available in Pom.xml - it will define which path and what jar name)
you will have the Core JAR files of each module.
Open those jar files using any decompiler , you will be able to find the class/java files in it..
Here is your complete solution.
If while creating war file, you have to make sure that you have added the code.
Otherwise, do one thing.
Deploy the war file in your server, may be on tomcat server.
To deploy the war file, you need to put that war file in webapps folder (C:\ASHIS_CODE\apache-tomcat-9.0.65\webapps).
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After putting, you need to restart your tomcat server.
Then one folder with same name as of your war file name, will be created in side webapps folder.
Open that folder in your eclipse or any other ide, that folder contains your project code.
** Hope this clears your issue.
Instead of using a certain jar in my WEB-INF/lib folder, I want to use its source code (same directory structure and everything) in my WEB-INF/classes folder, so that I may be able to modify its classes more story.
Yet (re)starting my tomcat after deleting the original jar and uploading the corresponding directory into WEB-INF/classes gives me the following error:
SEVERE: Error configuring application listener of class no.something.something1.http.LifecycleListener
java.lang.ClassNotFoundException: no.something.something1.http.LifecycleListener
I am certain that the directory path is the same as the one inside the jar. Also, I have previously tried using classes in my WEB-INF folder for this web application, and tomcat has also been unable to load them, for some reason.
Does anyone know how I go about troubleshooting this error?
Tomcat can only load .class files, it doesn't know what to do with raw source code files. Tomcat doesn't do hot loading of .class files like that anyway. You would have to restart the application or server after you recompiled them either way, packaging them as a .war isn't that much of a burden either way once you automate it.
If you take the time to automate the build and deployment of a proper .war you can just rebuild the .war and it will automagically undeploy and redeploy the application itself, which is many times faster than restarting the entire server.
You can't do what you are trying to do the way you are trying to do it. Tools like JRebel address these issues, but I don't find them as useful as their marketing makes them sound.
You could use embedded tomcat (or embedded jetty) to map directory structure of the application as you like. It probably will require some tinkering if you need some JNDI resources within your application but still worth the trouble.
Here's an example
I have installed and configured tomcat+solr on my personal linux machine and windows as well. I was able to get them working fine. I'm very new to Java and how the file structure works. (i.e. knowing where to put war files and what WEB-INF is) So now that I am ready to install solr and configure it on my clients shared hosting plan, the directions are different from what I did before. I dont want to mess this up and apparently the webserver reboots daily and I dont think I can do it manually which means I have one shot at this every day.
Here is the directions for installing a tomcat servlet on his hosting provider:
http://www.apluskb.com/scripts/Where_do_I_put_my_answer1186.html
As you can see I need to install solr under the html/WEB-INF directory, but read what it says.. its very confusing:
"All Servlets should be uploaded in the /html/WEB-INF/classes directory. Any unpacked custom classes and resources should be uploaded in the /html/WEB-INF/classes directory, while classes and resources packed in Jar files should be uploaded to /html/WEB-INF/lib."
uhh... so which is it? /classes? or /lib? I dont think they explain that very well and I'm a little confused by this statement. Also what exactly do I install? With a normal solr install, solr is put somewhere else, the war file is copied into tomcat and the rest of solr is referenced using some kind of XML configuration file.
Also, since I'm a little new to Java and servlets, can someone explain the tomcat file structure to me (in great detail will definitely get you a +1 from me) and where things should go and why?
Thanks in advance!
Web application structure is defined by J2EE spec, it's not limited (or specific) to Tomcat per se. Here is a detailed tutorial covering its layout. Briefly, however, it's as follows:
There a base (root, home, whatever you want to call it) folder which serves as root of web application, everything else goes under it.
All public stuff (html, images, CSS, javascript, JSP, what have you) goes under that folder (directly or via subfolders).
There's one special folder, also located directly under root, called WEB-INF. It contains non-public stuff, like application descriptor (web.xml), classes (which go into WEB-INF/classes folder), libraries (WEB-INF/lib) and possibly configuration files.
Application can be deployed either using expanded structure above or as WAR (web archive) which is basically an archive containing everything above starting at root folder level (but not including root).
The distinction between classes and lib folders is simple: all packaged libraries (JAR files) need to go into lib; all unpackaged classes (and resource files that need to be in classpath) have to go into classes preserving their directory structure (e.g. com.mypackage.Blah class should go into classes/com/mypackage/)
In your case, it looks like you can only have one web application deployed and it has to be deployed to /html folder. If you're deploying a war file, you need to extract it to that directory (e.g. from within that /html folder run jar xvf solr.war or whatever it's called).
I'm currently fixing a JSP project and it currently has a seemingly random collection of .class files in it's Tomcat's WEB-INF folder. As a way of simplifying this, I was planning to get .java files from these classes straight from SVN to WEB-INF folder on server and I got that to work but what would be the simplest way of compiling these? Of course I could create a cronjob which would compile all the classes during the night but it seems like a bit of hassle.
I know that our project management is a bit f*cked up and the correct of deploying applications on to a server would probably be to use WAR files. I'm trying to fix this in small incremental steps because the project is quite large and in use all the time.
Tomcat only compiles the .jsp files, so you'll have to do the compile the .java files yourself, one way or another.
Most robust solution would be to create an ant task that built a .war file for the entire project and then pushed that to Tomcat (or use Maven2 to achieve same). While that will require some work now, it will save you a ton of effort in the long run.
You might consider building a jar file from the *.java files on your build/dev box, then pushing that jar file to the server. Storing class files in VCS is a really bad idea.
Another approach might be to do the following
Assuming:
/opt/apache-tomcat/
Holds your app server, create something like this:
/opt/build/
Check out your files into the build directory then use one or more scripts to copy
/opt/build/my-app/ -->
/opt/apache-tomcat/webapps/my-app/
Once you have that kind of working, try to get a repeatable (and verifiable) build working. Ideally a war file.