A rudimentary Java program to read (i.e. simply inflate) git object files.

Read.java

package gitchen;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.util.Arrays;
import java.util.zip.InflaterInputStream;

// a class to look into the private parts of your git repo
public class Read {

	// path to the object store of your git repo: .git/objects/
	static String path = "~/projects/test/.git/objects/";
	
	public static void main(String[] args) throws Exception {
		if (args.length != 1) {
			System.out.println("Please give a SHA as argument.");
			return;
		}
		String sha = args[0];
		String prefix = sha.substring(0, 2);
		String rest = sha.substring(2);
		File file = new File(path+prefix+"\\"+rest);
		FileInputStream fin = new FileInputStream(file);
		// how many bytes to read? Create the array to take them.
		byte[] fileContent = new byte[(int) file.length()];
		fin.read(fileContent);
		ByteArrayInputStream bais = new ByteArrayInputStream(fileContent);
		InflaterInputStream iis = new InflaterInputStream(bais);

		String result = "";
		byte[] buf = new byte[5];
		int rlen = -1;
		while ((rlen = iis.read(buf)) != -1) {
			result += new String(Arrays.copyOf(buf, rlen));
		}
		System.out.println("Decompress result: \n" + result);
		// for quality programming, this would belong into a finally block, of course:
		fin.close();
	}

}

Neat! :)