How to reliably detect file types?

Question

Objective: given the file, determine whether it is of a given type (XML, JSON, Properties etc)

Consider the case of XML - Up until we ran into this issue, the follow

Answer 1

For those who do not need very precise detection (the Java 7's Files.probeContentType method mentioned by rjdkolb)

Path filePath = Paths.get("/path/to/your/file.jpg");
String contentType = Files.probeContentType(filePath);

Answer 2

File type detection tools:

• Mime Type Detection Utility
• DROID (Digital Record Object Identification)
• ftc - File Type Classifier
• JHOVE, JHOVE2
• NLNZ Metadata Extraction Tool
• Apache Tika
• TrID, TrIDNet
• Oracle Outside In (commercial)
• Forensic Innovations File Investigator TOOLS (commercial)

Answer 3

Apache Tika gives me the least amount of issues and is not platform specific unlike Java 7 : Files.probeContentType

import java.io.File;
import java.io.IOException;
import javax.activation.MimeType;
import org.apache.tika.Tika;

File inputFile = ...
String type = new Tika().detect(inputFile);
System.out.println(type);

For a xml file I got 'application/xml'

for a properties file I got 'text/plain'

You can however add a Detector to the new Tika()

<dependency>
    <groupId>org.apache.tika</groupId>
    <artifactId>tika-core</artifactId>
    <version>1.xx</version>
</dependency>