SecurityException: Unable to create temporary file with applet

Question

My applet tries to write a temp file
try {
          File temp = java.io.File.createTempFile("student", ".log");
          strFilename = temp.getAbsolutePath();
} catch (IOException e1) {
          e1.printStackTrace();
}But when I run, it throws an exception:
java.lang.SecurityException: Unable to create temporary file
I tried to sign the applet, as to http://www.developer.com/java/data/article.php/3303561 but it's still the same.
There's another way: using java.policy,
grant {
  permission java.security.AllPermission;
};but it seems to be not very gentle. Could you show me the solution please? Thanks in advance.
Cheers,

Answer 1

Yes, that's what I found. Here is the summary to do it, hope it helps someone else:
1. Create key for signed jar:
keytool -genkey -keystore abc.com -keyalg rsa -dname "CN=Abc, OU=Def, O=GHI, L=KLMN, ST=OP, C=XY" -alias TheCert -validity 3600 -keypass password -storepass password2. Make jar file
3. Sign the jar file
jarsigner -keystore abc.com -storepass password -keypass password -signedjar SignedAppletTest.jar OrgAppletTest.jar TheCertIt works for me.
I'd like to thank harmmeijer and everyone who interests.
Cheers,