Best practice to store temporary data for a webapp [duplicate]

Answer 1

A web container provides a context attribute that points to a temp directory:

Servlet spec SRV.3.7.1 Temporary Working Directories

A temporary storage directory is required for each servlet context. Servlet containers must provide a private temporary directory per servlet context, and make it available via the ServletContext.TEMPDIR (javax.servlet.context.tempdir) context attribute. The objects associated with the attribute must be of type java.io.File.

Example :

File appTempDir = getServletContext().getAttribute(ServletContext.TEMPDIR);
File tempFile = File.createTempFile("process1", ".txt", appTempDir);
tempFile.deleteOnExit();
try {
    ...
} finally {
    tempFile.delete();
}