core/src/main/java/org/springframework/security/access/expression/method/DefaultMethodSecurityExpressionHandler.java
protected MethodSecurityExpressionOperations createSecurityExpressionRoot(
			Authentication authentication, MethodInvocation invocation) {
		MethodSecurityExpressionRoot root = new MethodSecurityExpressionRoot(
				authentication);
		root.setThis(invocation.getThis());
		root.setPermissionEvaluator(getPermissionEvaluator());
		root.setTrustResolver(getTrustResolver());
		root.setRoleHierarchy(getRoleHierarchy());
		root.setDefaultRolePrefix(getDefaultRolePrefix());

		return root;
	}
protected MethodSecurityExpressionOperations createSecurityExpressionRoot(
			Authentication authentication, MethodInvocation invocation) {
		MethodSecurityExpressionRoot root = new MethodSecurityExpressionRoot(
				authentication);
		root.setThis(invocation.getThis());
		root.setPermissionEvaluator(getPermissionEvaluator());
		root.setTrustResolver(getTrustResolver());
		root.setRoleHierarchy(getRoleHierarchy());
		root.setDefaultRolePrefix(getDefaultRolePrefix());

		return root;
	}
Creates the root object for expression evaluation.