compiling java each time properties file is changed

>>However each time I change the location of the input file

Explain, please

Make sure you've closed the Properties input stream before you try to read it again

I cd to the directory where the properties file exists.The properties file has a property called inputfile.
I edit thisfile, by changing the value to some other filename
For eg inputFile=file1.dat- I compile my java code then run the app- the data from file1.dat is used by the java app.
Now,say I changed the filename to file2.dat and did not compile the code and ran the app- the data from file1.dat is still used.I have to compile and then run in order for file2 to be used.
Nothing has changed within any of the java files only an external properties file is being changed and does not need to be compiled.

Thanks for the feedback-
I am not using an input stream to read the properties file, this is how I do it:
Properties props = new Properties();
File data = new File(props.getProperty("inputFile"));
File abbreviations = new File(props.getProperty("abbFile"));
File sic=new File(props.getProperty("sic"))
The only thing that changes in the properties file is the property "inputFile"- I am not sure why consecutive runs is still remembering the old property,unless I compile and then run?

>>
Properties props = new Properties();
File data = new File(props.getProperty("inputFile"));
>>

Not possible. 'props' is empty

sorry- I was wrong.
       java.net.URL url = ClassLoader.getSystemResource("app.properties");
            InputStream is = url.openStream();
            props.load(is);
            is.close();
Then I read the properties-I have already closed the i=InputStream

That's fine. Can you show me the *re*reading code?

Thanks for the response- I thinkI have figured out what is happening. As a part of the build process I was copying the properties to another location, hence each time  I was editing the properties file, the old file was being used.
Thanks

OK - glad it's working