The security properties file java.security specifies the location of the
system-wide security policy files. In turn, these security policy files
affect the behavior of all Java applications run by the associated JVM.
The -Djava.security.policy command-line argument allows the user to
specify the location of a security policy property file.
java ... -Djava.security.policy= ...
The policy file specified in the example above does *not* replace the
system-wide policy files. Instead, the specified policy file is used in
conjunction with the system-wide policy files specified in the security
properties file.
At times, this aggregation of policies is undesirable. In these cases,
it is possible to use a specific security policy file instead of the
system-wide policy files. To specify such a file, use a double equals
sign ("=="), as in the example below:
java ... -Djava.security.policy== ...
Only the specified policy file will be used. All others will be
ignored.
