Hash table to keep track of all classloaders and string buffers for reading URLs and class files. The rest is beyond the scope of this article. SecurityManager to set security policy. For each resource a check is performed to grant access. Security manager controls the creation of class loaders.
Applications set security manager once.
Security manager first is defined and then implemented in code. We have seen that there are two basic aspects to security in the Java programming environment. In the sandbox model, the bytecode verifier, classloader, and security manager all work in a cooperative manner to strengthen the security features of Java. It has been said that the only really secure machine is one which is enclosed in a room with no entry capability, no network connectivity, and no console. Perhaps in time that requirement will be extended to no power also.