How a JAR file can read an external properties file

Question

We have a connection pooling component (JAR file) for one of our application. As of now the application connection details are bundled with-in the JAR file (in .proper

Answer 1

Simplest way, use the -D switch to define a system property on a java command line. That system property may contain a path to your properties file.

E.g

java -cp ... -Dmy.app.properties=/path/to/my.app.properties my.package.App

Then, in your code you can do ( exception handling is not shown for brevity ):

String propPath = System.getProperty( "my.app.properties" );

final Properties myProps;

if ( propPath != null )
{
     final FileInputStream in = new FileInputStream( propPath );

     try
     {
         myProps = Properties.load( in );
     }
     finally
     {
         in.close( );
     }
}
else
{
     // Do defaults initialization here or throw an exception telling
     // that environment is not set
     ...
}