http://scjp4u.com Just another WordPress weblog Wed, 28 Jul 2010 04:21:01 +0000 http://wordpress.org/?v=2.8.4 en hourly 1 http://scjp4u.com/how-to-instantiate-an-instance-of-the-inner-class.html http://scjp4u.com/how-to-instantiate-an-instance-of-the-inner-class.html#comments Wed, 28 Jul 2010 04:21:01 +0000 admin http://www.ucertify.com/article/index.html?id=126908 Una instancia de la clase interna sólo puede existir dentro de una instancia de la clase externa y tiene acceso directo a los métodos y campos de su instancia envolvente. Con el fin de crear instancias de una clase interna, uno tiene que crear instancias de la clase externa primero y luego crea el objeto interno dentro del objeto exterior con la siguiente sintaxis: = InnerObject OuterClass.InnerClass outerObject.new InnerClass (); pregunta de práctica Descarga y guía de estudio para GSSP -Java para el examen. material de estudio gratuito para CX310-055 Java 5.0 examen.

]]> http://scjp4u.com/how-to-instantiate-an-instance-of-the-inner-class.html/feed 0 http://scjp4u.com/replication.html http://scjp4u.com/replication.html#comments Tue, 27 Jul 2010 06:56:06 +0000 admin http://www.ucertify.com/article/index.html?id=124713 process group. A process can join a group, which is much like opening a file; the process is added to the group, but is also provided with a checkpoint containing the current state of the data replicated by group members. Processes can then send events to the group and will see incoming events in the identical order, even if events are sent concurrently. Membership changes are handled as a special kind of platform-generated event that delivers a new membership view to the processes in the group. Levels of performance vary widely depending on the model selected. Transactional replication is slowest, at least when one-copy serializability guarantee is desired. Virtual synchrony is the fastest of the three models, but handling of failures is less rigorous than in the transactional model. State machine replication lies somewhere in between; the model is faster than transactions, but much slower than virtual synchrony. The virtual synchrony model is popular because it allows the developer to use either active or passive replication. In contrast, the state machine replication and transactional replication are highly constraining and are often embedded into products at layers where end-users could not be able to access them. Database replication: Database replication can be used on many database management systems, usually with a master/slave relationship between the original and the replicated copies. The master logs the updates, which then ripple through to the slaves. Each slave outputs a message stating that it has received the update successfully, thus allowing the sending (and potentially re-sending until successfully applied) of subsequent updates. In multi-master replication the updates can be submitted to any database node which then ripple through to other servers, is often desired, but introduces substantially increased costs and complexity which may make it impractical in some situations. The most common challenge that exists in multi-master replication is transactional conflict prevention or resolution. Most synchronous or eager replication solutions perform conflict prevention, while asynchronous solutions have to perform conflict resolution. For instance, if a record is changed on two nodes simultaneously, an eager replication system would detect the conflict before confirming the commit and aborting one of the transactions. A lazy replication system would allow transactions to commit as well as run a conflict resolution during resynchronization. The resolution of such a conflict may be based on a timestamp of the transaction, on the hierarchy of the origin nodes or on much more complex logic, which decides consistently on all nodes. Database replication becomes difficult when it scales up. Usually, the scale up goes with two dimensions, horizontal and vertical: horizontal scale up has more data replicas, vertical scale up has data replicas located further away in distance. Problems raised by the horizontal scale up can be alleviated by a multi-layer multi-view access protocol. Vertical scale up runs into less trouble since internet reliability and performance are improving. Disk storage replication: The active storage replication is usually implemented by distributing updates of a block device to several physical hard disks. Thus, any file system that is supported by the operating system can be replicated without modification, as the file system code works on a level above the block device driver layer. It is implemented either in hardware or in software. The most basic method is disk mirroring, typical for locally-connected disks. Notably, the storage industry narrows the definitions, so mirroring is a local operation. A replication is extendable across a computer network, so the disks can be located in physically distant locations. The purpose is to avoid damage done by, and improve availability in case of local failures or disasters. Pass Sun Certified MySQL 5.0 Database Administrator Part II exam

]]> http://scjp4u.com/replication.html/feed 0 http://scjp4u.com/what-is-the-codepointat-method.html http://scjp4u.com/what-is-the-codepointat-method.html#comments Sat, 24 Jul 2010 09:16:42 +0000 admin http://www.ucertify.com/article/index.html?id=126914 El codePointAt () devuelve el carácter (punto de código Unicode) en el índice especificado. El índice se refiere a los valores char (unidades de código Unicode) y oscila entre 0 y length () - 1. El siguiente es el formato general del método: public int codePointAt (int index) Si el valor char se especifica en el índice dado está en el sucedáneo de alta gama, el índice es menor que la longitud de esta cadena, y el valor char en el índice está en el rango bajo de alquiler, a continuación, el punto de código adicional correspondiente a este par suplente es devuelto. De lo contrario, el valor char en el índice dado es devuelto. Haga clic aquí para descargar CX310-055 guía de estudio de prueba y la cuestión práctica.

]]> http://scjp4u.com/what-is-the-codepointat-method.html/feed 0 http://scjp4u.com/what-is-transactionrolledbackexception.html http://scjp4u.com/what-is-transactionrolledbackexception.html#comments Sat, 24 Jul 2010 07:37:19 +0000 admin http://www.ucertify.com/article/index.html?id=4101388 Descargar guía de preguntas y 092-CX310 para el examen.

]]> http://scjp4u.com/what-is-transactionrolledbackexception.html/feed 0 http://scjp4u.com/mysql.html http://scjp4u.com/mysql.html#comments Sun, 18 Jul 2010 04:15:27 +0000 admin http://www.ucertify.com/article/index.html?id=124712 Deployment of MySQL: MySQL can be built and installed manually from the source code, but this approach can be tedious so it is more commonly installed from a binary package unless special customizations are required. On most Linux distributions the package management system can download and install MySQL with minimal effort, though further configuration is often required to adjust the security and optimization settings. Though MySQL began as a low-end alternative to the more powerful proprietary databases, it has gradually evolved to support higher-scale needs as well. It is still most commonly used in small to medium scale single-server deployments, either as a component in a LAMP based web application or as a standalone database server. Much of MySQL's appeal originates in its simplicity and ease of use, which is enabled by an ecosystem of open source tools such as phpMyAdmin. In the medium range, MySQL can be scaled by deploying it on more powerful hardware, such as a multi-processor server with gigabytes of memory. There are however limits to how far the performance can scale on a single server, so on larger scales, multi-server MySQL deployments are required to provide improved performance and reliability. A typical high-end configuration can include a powerful master database which handles data write operations and is replicated to multiple slaves that handle all the read operations. The master server synchronizes continuously with its slaves so that in the event of failure, a slave can be promoted to become the new master, thus minimizing the downtime. Further improvements in performance can be achieved by caching the results from database queries in memory using memcached, or breaking down a database into smaller chunks called 'shards' which can be spread across a number of distributed server clusters. Best exam simulation free download CX310-811

]]> http://scjp4u.com/mysql.html/feed 0 http://scjp4u.com/mysql-internals-replication.html http://scjp4u.com/mysql-internals-replication.html#comments Fri, 16 Jul 2010 07:58:33 +0000 admin http://www.ucertify.com/article/index.html?id=129810 Si es correcto el registro puede ser garantizada por el registro en el formato de declaración, a continuación, formatee declaración deberá ser utilizado. De lo contrario, formato de registro se utilizará. Pase CX310-811 de certificación

]]> http://scjp4u.com/mysql-internals-replication.html/feed 0 http://scjp4u.com/what-is-the-java-security-permission-class.html http://scjp4u.com/what-is-the-java-security-permission-class.html#comments Thu, 15 Jul 2010 07:42:49 +0000 admin http://www.ucertify.com/article/index.html?id=133373 La clase java.security.Permission es una clase abstracta para representar el acceso a un recurso del sistema. En él se definen las funciones esenciales para todos los permisos. Cada instancia permiso es normalmente genera haciendo pasar una o más parámetros de cadena al constructor permiso. Todos los permisos tienen un nombre, así como funciones de resumen para la definición de la semántica de la subclase permiso especial. El objeto de esta clase incluye un "acciones" de lista que muestra las acciones que se permiten para el objeto.

• Conviértete del GIAC certificados.

]]> http://scjp4u.com/what-is-the-java-security-permission-class.html/feed 0 http://scjp4u.com/what-is-the-java-security-unresolvedpermission-class.html http://scjp4u.com/what-is-the-java-security-unresolvedpermission-class.html#comments Wed, 14 Jul 2010 12:52:13 +0000 admin http://www.ucertify.com/article/index.html?id=133374 La clase java.security.UnresolvedPermission se utiliza para mantener los permisos que fueron "resueltos" cuando la política se ha inicializado. Un permiso sin resolver es aquella cuyo real de las clases de permisos aún no existe en el momento de inicializar la política. Cada vez que un recuerdo se ha hecho para el estado interno de una política de seguridad, que se expresa normalmente por los objetos de permisos que están asociados a cada código fuente. Es posible que cuando la política se ha inicializado, el actual código que implementa una clase de permiso en particular todavía no ha sido cargado y se definen en el entorno de aplicaciones Java. material de estudio gratuito para GSSP-Java examen.

]]> http://scjp4u.com/what-is-the-java-security-unresolvedpermission-class.html/feed 0 http://scjp4u.com/what-is-the-getfeature-method.html http://scjp4u.com/what-is-the-getfeature-method.html#comments Wed, 14 Jul 2010 12:22:43 +0000 admin http://www.ucertify.com/article/index.html?id=133384 El getFeature () es usado para buscar el valor de una marca característica. El nombre de la característica es cualquier plenamente cualificados URI. Un validador puede reconocer a un nombre de la función, pero que temporalmente puede ser capaz de devolver su valor. Estos valores de las mismas puede estar disponible sólo en contextos específicos, como antes, durante o después de una validación. El siguiente es el formato general del método: public boolean getFeature (String nombre) throws SAXNotRecognizedException Haga clic aquí para descargar GSSP-Java prueba guía de estudio y la cuestión práctica.

]]> http://scjp4u.com/what-is-the-getfeature-method.html/feed 0 http://scjp4u.com/what-is-the-setproperty-method.html http://scjp4u.com/what-is-the-setproperty-method.html#comments Wed, 14 Jul 2010 12:22:40 +0000 admin http://www.ucertify.com/article/index.html?id=133385 El setProperty () método establece el valor de una propiedad. Un validador puede reconocer a un nombre de propiedad, pero no puede ser capaz de cambiar el valor actual. Los valores de propiedad puede ser inmutable o mutable sólo en contextos específicos, como antes, durante o después de una validación. Los validadores no están obligados a reconocer fijar ningún tipo de nombres de propiedades específicas. El siguiente es el formato general del método: public void setProperty (String nombre, objeto Object) throws SAXNotRecognizedException, SAXNotSupportedException pregunta de práctica Descarga y guía de estudio para GSSP-Java para el examen.

]]> http://scjp4u.com/what-is-the-setproperty-method.html/feed 0