Sign a JAR File That Never Expires

1. Download Java JDK.
2. Go to the JDK bin folder with command prompt with full administrator access/permission.
3. Create a certificate that expires 50 years later: keytool -genkey -alias sakra -validity 18250
   Give a password and some information.
4. Run: jarsigner jarname.jar sakra
   It prompts the password you gave for the certificate. It put my jar file to the bin folder! It is easier.
5. That's all, it is signed.