What is RMI, JDBC, Java Swing GUI, XML, DOM, EJB, J2EE?
Reference for technical terms related with Java development, such as RMI, JDBC, Java Swing GUI, XML, DOM, EJB, and J2EE.
Java Swing GUI
Java Swing GUI is the set of Classes which is essential to build up the Java client applications.
To take the best advantage of these Classes, we have to understand the approach called Model-View-Controller. Especially this is true for JTable, JTree and the subclasses of JTextComponent. With Model-View-Controller architecture, the centralized data can be shared by client programs over the net. Another important point about programming GUI based on Swing is that updating the GUI should be done within the Event-dispatching-thread. We must take care about this rule especially for the GUI which is updated by the change of data on the server-side. (In case that Model resides on the server and View on the client, updating View should be done within Event-dispatching-thread.)
JavaRMI
RMI is short for Remote Method Invocation. Java RMI enables elements of our Java programs to take some actions on other Java elements in remote machine. This Java API is essentail for EJB, the core API in J2EE.
JDBC
JDBC is the set of interfaces for connecting to SQL table. With JDBC, we can query and update the data stored in the SQL tables within our Java programs. By this way, any Java object can be saved into SQL tables. This Java API is essentail for EJB, the core API in J2EE.
XML
XML is short for Extended Markup Language. It represents the contents of data along with its data structure. We can define something like the template (which is called Data Type Definition, DTD for short) which is suitable for the structure of the intended data. Then, the actual data can be written in the text file along with the tags defined in our DTD. This text file is called XML document and can be parsed (read and analyzed) by the many XML-aware applications. Any objects in the world can be represented in XML and the XML-aware applications can touch any fragments of data in the XML document. Objects represented in XML can be exchanged between the XML-aware applications and such objects can be treated in the different ways according to the purpose of each application. Thus XML gave us Freedom of data exchange!
DOM
DOM is short for Document Object Model. DOM is the interface for accessing the arbitrary elements of XML document. Based on XML document, we can generate the DOM objects (the instances of DOM interface). Then, through the DOM objects, we can modify/delete any tree node of the data structure tree, or add the new tree node. The modified DOM objects can be saved as XML document.
EJB
Enterprise Java Beans (EJB for short) is the specification and guideline, which suggests us the sophisticated usage of Java RMI and JDBC. This spec defines what your remote objects should be, what the remote server must be responsible for and so on. Your EJB compliant remote components, which are held on EJB compliant server, can store the data sent from the client programs into the RDB, and vice versa. Along with this specification, we can take the full advantage of Java RMI and JDBC. EJB is the core specification of J2EE.
J2EE
Java2 Enterprise Edition (J2EE for short) is the specification and guideline for building the system which consists of EJB, JSP, JMS, JNDI and so on. The core of J2EE is the specification called Enterprise Java Beans (EJB for short), which is responsible for Object Persistence by Java RMI and JDBC. EJB plays a role of Model in our system. Your EJB compliant remote components, which are held on EJB compliant server, can store the data sent from the client programs into the RDB, and vice versa. And JSP, another specification of J2EE, will reflect the Model to View, i.e. JSP can generate the HTTP response for the Web browsers or WAP browsers.
Sand bag security
Security system supplied with JDK1.1 and later. The main subject related with the security in JDK1.1 was how to protect the runtime environment from wicked Applets.
Applets developed by JDK1.1 or higher have the ability to access the system resources of the local machine. They are more useful than the ones based on JDK1.0, but there is the possibility that the wicked Applets do harm. To prevent wicked Applets from attacking, the users can allocate the previlages for each URL where the Class files come from. The previlages can also be allocated per the digital signature on JAR files.
Since JDK1.2, this approach is applied also to the Java programs other than Applets. In the text file called policy file on the runtime environment, the users can specify the range of actions to be allowed. According to policy file, SecurityManager in the Java programs checks if the intended actions are allowed before they are taken.
Digital signature
Digital signature is the unique object which is generated based on the Java object. (Note that the Java object itself remains unchanged.) The key is required to generate the digital signature. Assuming that the key belongs to only one person, we can think of the generated digital signature unique in the world. This uniqueness guarantees for both of the integrity of the of the Java object and the identity of the signer.
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All the APIs for Servlet/JSP introduced by this web site are now included in Bento framework:
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