MethodType::fromMethodDescriptorString default to use the system class loader in resolving classes per the given descriptor string if the loader parameter is null. Since this method accesses the system class loader on behalf of the caller, it should do a security permission check as ClassLoader::getSystemClassLoader.
Webrev: http://cr.openjdk.java.net/~mchung/jdk14/8229785/webrev.00/ CSR: https://bugs.openjdk.java.net/browse/JDK-8230777 Thanks Mandy
