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Java find the relative path of the configuration file in the war file

I am trying to access the config.properties file which was previously placed in the config folder. after some research, I moved it to the WEB-INF folder. but even after I moved it, it still return java.lang.NullPointerException whenenver I run my my program. code used to store some password information as below:
ClassLoader resource = ConnectionManager.class.getClass().getClassLoader();
URL path = ConnectionManager.class.getClass().getResource("/WEB-INF/config.properties");
props.load(new FileInputStream(path.getFile()));
String passwordds = props.getProperty("datasource.password");
these are the codes that I found and I try to use it but still I got the null exception.
I cannot use absolute path due to this project will be deploy to production server as in .war file. please advise what is the best way as I am still beginner.

You should check the war your build tool generated, and find where your config file really are.
For maven project, the default resource dir is /src/main/resources/
So /src/main/resources/config.properties will be put at /WEB-INF/classes/config.properties in a war.
You can use getClass().getResourceStream("/config.properties") (getResource sometimes not work will in j2ee environment) to get it.

Spring Boot: Unable to read resources in lib/*.jar using a class in lib/*.jar

Iam using spring boot org.springframework.boot.loader.JarLauncher to run my self executable spring boot app jar.
Now, I have my self executable jar packed like this (For brevity Iam just adding the files only that are needed to show the problem):
Main.jar
---META-INF
---lib
---a.jar
---com
---comp
---Abc.class
---folder1
---1.txt
---2.txt
---b.jar
and so on.
In my Abc.class Iam trying to load the resource 1.txt which is working fine when I run it in eclipse; but the story starts when I run using command line as self executable jar. I was not able to read that resource and ends up with null pointer error.
After reading few threads, I learnt that my IDEs does some magic on Class Loaders and so it was working fine, which will not be the case when I run it as executable jar
This is how I was Loading the files and the all the possible options I have tried to no luck.
Option 1:
Abc.class.getResourceAsStream("\folder1\1.txt")
Option 2:
Abc.class.getClassLoader().getResourceAsStream("folder1\1.txt")
Option 3: Reading thread, I have tried considered the current thread class loader context as below too, But to no luck again
Thread.currentThread().getContextClassLoader().getResourceAsStream("folder1\1.txt")
Can any one advise. How should I write my code to be able to read my resource that is in the jar and by the class that is in the same jar ?
PS: Spring boot is not adding class-path entry to MANIFEST.MF and if I have to do something around that, how do I do that ? In-fact I tried -cp when running my jar setting it to current directory, but that have not worked either

In Spring, the best way to access a Resource is via Resource APIs. For a Classpath resource what you should use a ClassPathResource and it would look something like this:
Resource resource = new ClassPathResource("/my/resource.json", this.getClass());
After obtaining a Resource you can either get a File reference via getFile() or get an InputStream straight off by calling getInputStream().
Spring provides quite a few different implementations of the Resource interface, take a look at the list of known implementations in the docs

Use Spring's class ClassPathResource to load file from classpath.
For example you can read file into String like this from classpath:
String fileContent = FileUtils.readFileToString(
new ClassPathResource("folder1" + File.separator + "1.txt").getFile());
It doesn't matter what kind of build tool or project structure you are using as long as that file is on classpath.

Java file path in web project

I need to access the resource files in my web project from a class. The problem is that the paths of my development environment are different from the ones when the project is deployed.
For example, if I want to access some css files while developing I can do like this:
File file = new File("src/main/webapp/resources/styles/some.css/");
But this may not work once it's deployed because there's no src or main directories in the target folder. How could I access the files consistently?

You seem to be storing your CSS file in the classpath for some unobvious reason. The folder name src is typical as default name of Eclipse's project source folder. And that it apparently magically works as being a relative path in the File constructor (bad, bad), only confirms that you're running this in the IDE context.
This is indeed not portable.
You should not be using File's constructor. If the resource is in the classpath, you need to get it as resource from the classpath.
InputStream input = getClass().getResourceAsStream("/main/webapp/resources/styles/some.css");
// ...
Assuming that the current class is running in the same context, this will work regardless of the runtime environment.
See also:
getResourceAsStream() vs FileInputStream
Update: ah, the functional requirement is now more clear.
Actually I want to get lastModified from the file. Is it possible with InputStream? –
Use getResource() instead to obtain it as an URL. Then you can open the connection on it and request for the lastModified.
URL url = getClass().getResource("/main/webapp/resources/styles/some.css");
long lastModified = url.openConnection().getLastModified();
// ...

If what you're looking to do is open a file that's within the browser-visible part of the application, I'd suggest using ServletContext.getRealPath(...)
Thus:
File f = new File(this.getServletContext().getRealPath("relative/path/to/your/file"));
Note: if you're not within a servlet, you may have to jump through some additional hoops to get the ServletContext, but it should always be available to you in a web environment. This solution also allows you to put the .css file where the user's browser can see it, whereas putting it under /WEB-INF/ would hide the file from the user.

Put your external resources in a sub-directory of your project's WEB-INF folder. E.g., put your css resources in WEB-INF/styles and you should be able to access them as:
new File("styles/some.css");
Unless you're not using a standard WAR for deployment, in which case, you should explain your setup.

Typically resource files are placed in your war along with your class files. Thus they will be on the classpath and can be looked up via
getClass.getResource("/resources/styles/some.css")
or by opening a File as #ig0774 mentioned.
If the resource is in a directory that is not deployed in the WAR (say you need to change it without redeploying), then you can use a VM arg to define the path to your resource.
-Dresource.dir=/src/main/webapp/resources
and do a lookup via that variable to load it.

In Java web project, the standard directory like:
{WEB-ROOT} /
/WEB-INF/
/WEB-INF/lib/
/WEB-INF/classes
So, if you can get the class files path in file system dynamic,
you can get the resources file path.
you can get the path ( /WEB-INF/classes/ ) by:
this.getClass().getProtectionDomain().getCodeSource().getLocation().getPath()
so, then the next ...

Netbeans Built .jar doesn't work with class file inside

I had problems while finding the path of file(s) in Netbeans..
Problem is already solved (checked answer).
Today I noticed another problem: When project is finished,
I have to execute the generated .jar to launch the program, but it doesn't work because an error occurs: NullPointer (where to load a file) when accessing/openning jar outside Netbeans.
Is it possible to open a file with the class file in Java/Netbeans which works in Netbeans and even in any directory?
I've found already some threads about my problem in site but none was helpful.
Code:
File file = new File(URLDecoder.decode(this.getClass().getResource("file.xml").getFile(), "UTF-8"));

The problem you have is that File only refer to files on the filesystem, not files in jars.
If you want a more generic locator, use a URL which is what getResource provides. However, usually you don't need to know the location of the file, you just need its contents, in which case you can use getResourceAsInputStream()
This all assumes your class path is configured correctly.

Yes, you should be able to load a file anywhere on your file system that the java process has access to. You just need to have the path explicitly set in your getResource call.
For example:
File file = new File(URLDecoder.decode(this.getClass().getResource("C:\\foo\\bar\\file.xml").getFile(), "UTF-8"));

jboss: accessing file resource through java code?

I am reading properties file from java DAO implementation for loading properties object as in code given below
this.getErrorproperties().load(
new FileInputStream(new File("").getAbsolutePath()
+ "/conf/error/error.properties"));
While testing it works fine but when i try to deploy application on jboss 5 server. application deployment fails because absolute path is considered to be bin directory of jboss.
I want Jboss to find it relative to path of ear file. One more problem i face is my path relative to home path of project or ear file will be different for first and later.
Please suggest current approach programmers follow for such scenario. (I am a fresher)

You need to have your properties file in your classpath. If you have your properties file in the package foo.bar then you can load the properties file using,
this.getErrorproperties().load(getClass().getResourceAsStream("/foo/bar/error.properties"))
The leading slash in the path indicates an absolute path. Without the leading slash, the path is relative to the package of the class in.