`MethodType::fromMethodDescriptorString` has been changed in this release. When a security manager is present and the `loader` parameter is null, it performs a RuntimePermission("getClassLoader") security permission check. This check ensures that access to the system class loader is permitted.

Existing code that calls `MethodType.fromMethodDescriptorString(desc, null)` might get a `SecurityException` if access to the system class loader is denied. The security policy must be configured to grant the permission. Applications running without a security manager or with a non-null loader are not affected by this change.