The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.
Here's the basic structure of the GenSig
program. Place it in a file called GenSig.java
.
import java.io.*; import java.security.*; class GenSig { public static void main(String[] args) { /* Generate a DSA signature */ if (args.length != 1) { System.out.println("Usage: GenSig nameOfFileToSign"); } else try { // the rest of the code goes here } catch (Exception e) { System.err.println("Caught exception " + e.toString()); } } }
Notes:
The methods for signing data are in the java.security
package, so the program imports everything from that package. The program also imports the java.io
package, which contains the methods needed to input the file data to be signed.
A single argument is expected, specifying the data file to be signed.
The code written in subsequent steps will go between the try
and the catch
blocks.