从代码层面理解java的00截断漏洞

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URLDecoder;

public class T1 {
	public static void main(String[] args) {
		String path = "c://test.jsp"+URLDecoder.decode("%00")+"test.txt";
		System.out.println("filename:" + path);
		File file = new File(path);
		System.out.print("content:");
		try {
			FileInputStream fis = new FileInputStream(file);
			int b;
			while((b = fis.read()) != -1){
				System.out.print((char)b);
			}
			fis.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}