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This page lists help requests that have been submitted and are due to be answered. They cannot be answered immediately, but are listed here to show that they have not been ignored.
Questions that seek a subtle definition, explanation or clarification of specific programming features or concepts tend to be difficult to answer and are often classified as medium priority. This is because they are likely to be interesting to many readers, but need to be carefully thought through and worded so that the anwswer is clear, not more confusing.
Questions about relatively complex programming techniques like Java threads and JDBC tend to require longer answers and often slip into the medium priority category because of time constraints. This is a difficult trade-off because these questions also tend to be more interesting.
Q: How can I retrive data from two tables where these tables are in two different databases, e.g. Oracle and SQL Server.
Q: How should I pass information entered in the text input of a Frame to a database using JDBC? Can you give simple code for the form?
Q: Can we use one connection pool to access multiple databases?
Q: How can I save data from a database into files?
Q: How does communication occur between an application server and database server?
Q: How can I rotate an image using a mouse drag, as well as save it through Javascipt?
Q: I need the Javascript code for getting the all information about browser.
Q: I have a set of HTML pages, each containing links and popups. When a link is selected in one page, I would like to be able to display a specific popup in another page when it opens. What I really want to do then is share a Javascript variable between the pages. Although both pages share the same external Javascript file, the variables in this file always seem to get reinitialised between pages. Is there any way around this without having to do something on the server side? Effectively, all I want to be able to do is pass a parameter through an href attribute.
Q: How can I display a Javascript confirmation message and assign the user's response to a variable?
Q: I have generated dynamic buttons with background image and onmouseover, onmouseout and onclick events but the problem I encountered was that in the onclick event I want to change button background image. I to remove the other event handlers during the onclick event.
Q: Is there a way to call a Java method from Javascript?
Q: How can I use keyboard functions with Javascript?
Q: If wait() is called in a synchronised block, does the thread exit synchronised block without executing the remaining code?
Q: What is the difference between the wait(), suspend() and the sleep() methods.
Q: What is the difference between a normal synchronized and a static synchronized method?
Q: I have doubts about the Java 1.5 Callable interface. The start() is used to start a new thread and it will call the run(). But what about the call() method. How does it run in a thread?
Q: Which state does a thread enter after the completion of the sleep() method?
Q: Why do we say that thread execution occurs in parallel?
Q: What is a daemon thread?
Q: What is the difference between Multithreading and multiprocessing?
Q: How my JSP know that the client browser is not accepting cookies?
Q: What is the significance of setContentLength() and the isResponseCommited() method? And how do these methods effect the response generated by a servlet or JSP?
Q: Can we directly catch a JspTagException thrown by a custom tag?
Q: How can I write JSP code to take a user ID and password and maitain it in a database?
Q: How can I temporarily prevent people from attempting a login after failing more than 3 times?
Q: How can I show the values stored in my database table in a JSP text field using a servlet?
Q: What is the difference between a reference, instance and object in Java?
Q: What are the differences between a variable and an object?
Q: What is the difference between abstraction and polymorphism?
Q: When we define a local inner class within a method why can the local inner class access only final local variables and method parameters? Why not normal automatic variables? I did read a little about this, and I understood something about final values being frozen so that the JVM exectly knows what value will the inner class access. But I'm still not very clear. Please help me if possible.
Q: Is overloading polymorphism in Java?
Q: What data type are Java arrays and why are they indexed from zero?
Q: What is the implementation of destroy method in Java? Is it native or Java code?
Q: What is the diffrence between a front end language and back end language?
Q: If pointers are efficient for faster access to memory locations then why is it that the pointer concept has been eliminated in Java?
Q: The C++ language can also be executed on any platform, so how is Java different?
Q: Why can't we declare more than one public class in a source file?
Q: What is the difference between Calendar and Date?
Q: How do inheritance hierarchies designed for implementing an interface differ from those designed for extending a superclass?
Q: Why isn't the return type considered in method overloading?
Q: The superclass default constructor is automatically available in any subclass, so why aren't parameterized constructor available?
Q: Does a class inherit or an object? Somebody says that class extends but some says that object extend because class only provide boundary and object hold state(values). Please tell me what actually happens?
Q: Why are servlets initialised only once and only the same servlet instance is used to service all client requests?
Q: Which method we can override in the servlet lifecycle?
Q: What is the difference between instance pooling and thread pooling in Java servlets?
Q: What types of URL patterns can we use in a web.xml configuration for a servlet?
Q: How do controller servlets handle all servlets? Do we need to configure all servlets in web.xml or not?
Q: Can I pass servlet configuration parameters from one servlet to another?
Q: How do we get data from a JSP to a servlet, retrieve data from a database and return the result in the original JSP.
Q: How can servlets communicate with each other in a container?
Q: When I run Tomcat I get an error that says port 8080 has been used by JVM binding
Q: What is the difference between a standard SQL query and a stored procedure?
Q: If a subclass implements the Serializable interface, will the variables of the superclass be serialized or not?
Q: How can I discover any resources still remaining in the system after the program is exited. Such as, forgotting to close a connection or objects. Can you suggest any tools to help to locate these resources remaining?
Q: How can I send mail using a Java program?
Q: How can I create a fixed background using CSS?
Q: How can I check the format of an email address?
Q: How can I show alternate colours for each table row?
Q: Is there a way to get the whole arguments string without enumenrating the String[] args?
Q: How sessions are internally handled by server? Is it a physical file stored server side or any other mechanism?
Questions about specific applications tend to require more research and consideration, so they are given low priority. Questions that require development, testing or debugging are also likely to be given low priority, unless they are very useful or interesting in their own right. Generally, less interesting questions are also a low priority.
Q: How can I create a tab menu structure only in JSP and HTML not using the servlet concept.
Q: Despite closing database connection, I get a warning like "Closing a statement you left open, please do your own housekeeping" on a JBoss server. How can I fix this?
Q: How do I code a driver class?
Q: How do i get the Java version for Internet Explorer using Javascript?
java.lang.System.getProperty("java.version"); does not work with IE.
Q: I would like to transfer a file from client machine to an application server machine using a servlet without a browser window. Please provide a solution if it is possible.
Q: I want to create a survey form and display a confirmation page that shows all the options that the user selected.
Q: How many ways are there to get the ServletConfig and ServletContext objects?
Q: Can you give an example of using named RequestDispatcher forwarding?
Q: If I have been given date and time of a particular time zone, say America, Los Angeles, how can I find the time at that moment in some other time zone?
Q: How can I write a Java program to find the IP address for any Web site and return the server location or return the search engine address for the Web site?
Q: How can I encrypt and decrypt data in Java with 128 bit keys?
Q: How can I encrypt data using hashing techniques?
Q: Any Java program showing memory abstraction
Q: I constructed 3 packages in Java like c:\batch32\p1\p2. I am trying to import p2 classes in the source program of batch32 can you please explain complete syntax?
Q: What is the difference between an abstract class and an interface in terms of memory allocation?
Q: What is the difference between encapsulation and information hiding?
Q: What is Java and J2EE?
Q: I have three methods that I want to run on new threads. Instead of creating three classes that extend Thread, how I can spawn three new threads to run those methods?
Q: I want to change the border color of a dropdown select element. I tried adding all the parameters but it did not effect the drop down box.
.seSelector {
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 8pt;
font-weight: normal;
font-style: normal;
border: medium black;
border-color: #000000;
border-style: dotted;
border-width: 1px;
background-color: #FFFFFF;
width: 140px;
height: 24px;
}
Q: How can I maintain a dynamic menu in a Java Web application?
Q: What is Struts flow?
Q: I want to create subdomains for every state of the USA.
Q: Why is it neccessary to view your page in different browsers and why will it show differences in different browsers?
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