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How to specify a Java file path for both Mac and Ubuntu

I'm using IntelliJ and Spring and Java to locally develop an app on a Mac, and then deploy to a tomcat server on AWS, using Ubuntu 16.04.3 LTS (GNU/Linux 4.4.0-1048-aws x86_64).
I'm having trouble specifying the file path so that it works in both environments.
My code is
InputStream fileStream = new FileInputStream("src/main/resources/static/web/data/ReportDates.json");
JsonReader reader = Json.createReader(fileStream);
JsonObject reportDates = reader.readObject();
reader.close();
When I run locally, the file is read in correctly. It is located in:
src/main/resources/static/web/data/ReportDates.json
But when I deploy, that code results in the error message:
java.io.FileNotFoundException: src/main/resources/static/web/data/ReportDates.json (No such file or directory)
The actual location of the file on that machine turns out to be:
/opt/tomcat/webapps/automentor/WEB-INF/classes/static/web/data/ReportDates.json
How can I specify the file path so that it works correctly in both environments?

I have given up on using a single path. #Nicholas Pesa got me thinking -- since I use IDEA, I don't have a fixed WEB-INF folder, so it's easier for me to change the path that should be used than to move the file to a fixed location.
My code now uses:
String filepath = (new File("src/main/resources/static/web/data/ReportDates.json").exists()) ? "src/main/resources/static/web/data/ReportDates.json" : "/opt/tomcat/webapps/automentor/WEB-INF/classes/static/web/data/ReportDates.json";

How to pass variable file path to SQL*Loader on Linux

I'm creating .csv file and placing it in one location.
String location = "/APPL_TOP2/IMDD/apps/apps_st/appl/xxfin/12.0.0/bin/xe.csv";
Using exact path working fine on Windows but I need it to work on Linux client too.
String location = "$XXFIN_TOP\\12.0.0\\bin\\xe.csv";
If I'm using relevant path on Linux it is not working, showing Error
SQL*Loader-500: Unable to open file(/APPL_TOP2/IMDD/apps/apps_st/appl/xxfin/12.0.0/bin/xe.csv)
SQL*Loader-553: file not found
SQL*Loader-509: System error: No such file or directory

" Client is asking any option to pass relevant path client machine is Linux"
Paths in Linux have slashes which go the other way. So it should be this:
$XXFIN_TOP/12.0.0/bin/xe.csv

Creating a directory on client machine using applet

I have a self signed applet running in the browser, this applet should create a directory on the client machine using this code.
boolean success = (new File("myDir")).mkdirs();
if (!success) {
System.err.println("Directory creation failed");
}
However, when I run it in the browser (under Apache) and after accepting all the security warnings I can't find myDir directory on my machine.
Am I doing something wrong?

I guess you are not looking at the right place...
Given your code snippet, this directory will be created in the current working directory. To be sure where that is on your machine just try to see what the following code gives out :
System.out.println(System.getProperty("user.dir"));

You're not giving it an absolute path so it's creating myDir in the working directory that the browser runs it in, probably a temp dir, or even a "sandbox" area in some browsers.

Because you run applet in sandbox, so You cannot access into user machine resource.
Please see document:
Applet security

Reading File in J2ME

I became so much upset with this simple code segment:
FileConnection fc = (FileConnection) Connector.open("file:///root1/photos/2.png");
System.out.println(is.available());
byte[] fileBytes = new byte[is.available()];
int sizef = is.read(fileBytes);
System.out.println("filesize:"+sizef);
When I deploy this midlet in my mobile (with proper file location) It works properly i.e it shows proper filesize, but in the pc emulator it is constantly giving filesize of: 0. Obviously no Exception and I have the proper file in that location.
I am using j2mewtk sdk in netbeans 6.9. I tried uninstalling, installing wtk & netbeans.
Another thing is Everytime I run the emulator it creates C:\Users\Mahsruf\j2mewtk\2.5.2\appdb\temp.DefaultColorPhone6 new location like temp.DefaultColorPhone1,2,3,4 etc.
If I use jme SDK 3.0 in netbeans the file size is still 0, but now with a extra line in output window: [WARN] [rms ] javacall_file_open: _wopen failed for: C:\Users\Mahsruf\javame-sdk\3.0\work\0\appdb\_delete_notify.dat
What am I doing wrong?

This is not coding related issue. If multiple instances of the same emulator skin run simultaneously, the toolkit generates unique file paths for each one. For example, on Windows instances of DefaultColorPhone might have a file path name of workdir\appdb\temp.DefaultColorPhone1, workdir\appdb\temp.DefaultColorPhone2, and so forth.
Solution: The file workdir\appdb\DefaultColorPhone\in.use keeps track of the number of storage roots marked as in use. If the emulator crashes, you need to delete the in.use file

Error while migrating JSP code from Windows to Linux machine

I worked on a JSP code that is runnning on a Tomcat5.5 server in windows system .
I had to copy all the JSP code to a linux system and when I did the same I got an error stating below.
javax.servlet.ServletException: c:\tmp is not a directory
Readcsv.init(Readcsv.java:36)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
java.lang.Thread.run(Thread.java:636)
I modified a java code in the windows system without that c:\tmp directory and restarted the tomcat server and the tool worked fine.
When I replaced the modified java code of windows to the linux system, I still get the same error.
Note: Am accessing the linux server from windows using the url http://192.168.0.85:8080/CNA/uploadcsv.jspwhere 85 is the system number of linux.
Is there anything like tomcat has to be restarted for the linux version too? If so how to do the same?
UPDATE
This is where I have used the c:\tmp location in my code.
public class Readcsv extends HttpServlet {
private static final String TMP_DIR_PATH = "c:\tmp";
private File tmpDir;
private static final String DESTINATION_DIR_PATH ="/files";
private File destinationDir;
public void init(ServletConfig config) throws ServletException {
super.init(config);
tmpDir = new File(TMP_DIR_PATH);
if(!tmpDir.isDirectory()) {
throw new ServletException(TMP_DIR_PATH + " is not a directory");
}
String realPath = getServletContext().getRealPath(DESTINATION_DIR_PATH);
destinationDir = new File(realPath);
if(!destinationDir.isDirectory()) {
throw new ServletException(DESTINATION_DIR_PATH+" is not a directory");
}
}
How can I find the replacement for the temp path? The destination path works fine.
I exactly copied the code from this example

Don't hardcode disk file system paths in your code. That's only portability and maintainability trouble.
In case of temporary files, rather make use of File#createTempFile().
File tempfile = File.createTempFile("name", ".ext");
It will automatically create the temp file at the right location, regardless of the environment. You can however also obtain the tmp dir root location by System.getProperty("java.io.tmpdir");.
In case of resources which are to be read by your application, just put them in the runtime classpath or add their path to the runtime classpath. Then you can just obtain them from the classpath by getResource() and getResourceAsStream() methods on Class or ClassLoader.
InputStream input = getClass().getResourceAsStream("file.properties");
If you really need to have a fixed path outside the classpath, then rather define it in a properties file so that you at least have any control over the path from outside the application (so, without the need to change the code everytime).
String path = properties.getProperty("my.file.path");

it seems that your application try to read a csv file under "C:\tmp" which doesn't exist on your linux system.

You said you modified the code and redeployed it to Tomcat.
You probably just need to restart Tomcat to get it to pick up the new code. Until then, it will be running the old code and you will get the same error.
How you restart Tomcat depends on which Linux distribution you are running and how you installed Tomcat.